Balik bang. Cuti 3 hari boleh lepak 9... Bila lagi..??

For credits (hutang) transaction
There is one more thing to look out for: penalty for late payment

Couldn't find better literature but the following Indonesian website. Its language is a biy hard for me to completely understand, but the main point is that certain penalty on credit transactions are also categorized as riba. (Those with better Bahasa Indonesian understanding may want to give the source a try)

I just quote the "summary" as follows:

Jadi, anggapan sebagian orang bahwa syarth jaza’i secara mutlak itu mengandung unsur riba nasi’ah adalah anggapan yang tidak benar. Anggapan ini tidaklah salah jika ditujukan untuk transaksi-transaksi yang pada asalnya adalah utang-piutang, semisal jual-beli kredit dan transaksi salam.

Source:

http://pengusahamuslim.com/1713-serbaserbi-denda.html

I give you one of the solution (well, actually it's just temporary solution, not permanent solution)


Attached thumbnail(s)

Surah Al-Baqara, Verse 275:
الَّذِينَ يَأْكُلُونَ الرِّبَا لَا يَقُومُونَ إِلَّا كَمَا يَقُومُ الَّذِي يَتَخَبَّطُهُ الشَّيْطَانُ مِنَ الْمَسِّ ذَٰلِكَ بِأَنَّهُمْ قَالُوا إِنَّمَا الْبَيْعُ مِثْلُ الرِّبَا وَأَحَلَّ اللَّهُ الْبَيْعَ وَحَرَّمَ الرِّبَا فَمَن جَاءَهُ مَوْعِظَةٌ مِّن رَّبِّهِ فَانتَهَىٰ فَلَهُ مَا سَلَفَ وَأَمْرُهُ إِلَى اللَّهِ وَمَنْ عَادَ فَأُولَٰئِكَ أَصْحَابُ النَّارِ هُمْ فِيهَا خَالِدُونَ

Those who eat Riba (usury) will not stand (on the Day of Resurrection) except like the standing of a person beaten by Shaitan (Satan) leading him to insanity. That is because they say: "Trading is only like Riba (usury)," whereas Allah has permitted trading and forbidden Riba (usury). So whosoever receives an admonition from his Lord and stops eating Riba (usury) shall not be punished for the past; his case is for Allah (to judge); but whoever returns [to Riba (usury)], such are the dwellers of the Fire - they will abide therein.
(English - Mohsin Khan)

via iQuran app for Android

Tafsir:

Allah's statement,
﴿ذَلِكَ بِأَنَّهُمْ قَالُواْ إِنَّمَا الْبَيْعُ مِثْلُ الرِّبَواْ وَأَحَلَّ اللَّهُ الْبَيْعَ وَحَرَّمَ الرِّبَواْ﴾

(That is because they say: "Trading is only like Riba,'' whereas Allah has permitted trading and forbidden Riba) indicates that the disbelievers claimed that Riba was allowed due to the fact that they rejected Allah's commandments, not that they equated Riba with regular trade. The disbelievers did not recognize that Allah allowed trade in the Qur'an, for if they did, they would have said, "Riba is trade.'' Rather, they said,
﴿إِنَّمَا الْبَيْعُ مِثْلُ الرِّبَواْ﴾

(Trading is only like Riba) meaning, they are similar, so why did Allah allow this, but did not allow that, they asked in defiance of Allah's commandments.

Allah's statement,
﴿وَأَحَلَّ اللَّهُ الْبَيْعَ وَحَرَّمَ الرِّبَواْ﴾

(Whereas Allah has permitted trading and forbidden Riba) might be a continuation of the answer to the disbelievers' claim, who uttered it, although they knew that Allah decided that ruling on trade is different from that of Riba. Indeed, Allah is the Most Knowledgeable, Most Wise, Whose decision is never resisted. Allah is never asked about what He does, while they will be asked. He is knowledgeable of the true reality of all things and the benefits they carry. He knows what benefits His servants, so He allows it for them, and what harms them, so He forbids them from it. He is more merciful with them than the mother with her own infant.

Source:
http://www.qtafsir.com/index.php?option=co...d=122&Itemid=36

This post has been edited by abu.shofwan: Sep 18 2016, 08:34 PM

Yeah
There are many faces of riba. I only know a few. Most recent one (that I got to know) was the penalty applied on credit transaction.
I also find it difficult to escape riba, I guess everyone also suffer the same. Perhaps by allowing developers to act as loaners, we can find one way to escape since the transaction becomes buying from the source with deferred payment.
(on a side note: my family still live in a rented house)

This post has been edited by abu.shofwan: Sep 18 2016, 11:41 PM

Thanks. Point no. 2 a bit tldr (errr... TLTR la). Will revisit later when got time.
But in any case, IMO, if indeed developers can sell on deferred payment scheme, there is a possibility of riba-less transaction (and I'm talking only based on my shallow knowledge). It's just another option than with islamic bank. I'm happy to get more options.
Btw, point no 3... Can share a bit what you mean by {"-i" on it}?? Do you mean named as "xxx islamic"?? (for this I fully agree with you, they are likely "-i" in name only. The best option to my knowledge is bank islam malaysia berhad??)

true that. but money is one of the ribawi items, hence no "profit" is allowed if it is transacted with money. I mean, in this case you are loaning money, and you will pay with money - whether paid in one go or in installment.

"profit" is allowed if it is a normal "physical item" (say, a car, a house, smakfon, etc.) for credit payment. As the others have stated, you can sell iPhone 7 plus at RM 4k for one time payment, or a total of RM 4.1k for a three time payment. but this must be agreed when buying, cannot have conditional terms like: I will buy the iPhone 7 plus from you at RM4k, but If I cannot pay you in full then I will pay you RM 4.1k (i.e. in this example, both agree two prices may take effect).

Disclaimer:
There are a lot of things/rulings on islamic economics. I have to confess, I failed even normal economics (to the extent that during my school days getting a C score would be a success for me) - so I cannot grasp everything on islamic economics. However, I have heard before that inflation can be considered. (will try to find source later)

That example you quoted from previous post is money for money transaction. In this case, iirc other's explanation, it is counted as riba if the payment is more or late (or both).

In the case of your gift, the transaction is money for something (which I assume is not a ribawi thing like gold), the rules are more relaxed - if there is only one single buyer. If it's a collective buying, I don't know enough to answer. But there appears to be two transaction : the original transaction between you (the buyer) with the supplier (which I believe qualify under the relaxed terms I mentioned), and the second is between you and your sibling (which I do not know enough to say anything).

The truth is, jinn is makhluk ghoib. We mere mortals know but very little as we are not meant to interact with them, let alone study them.
It may be possible for jinn to "kacau rahim" since we have hadeeth that they can inhibit human body or parts of the body, suxh as the hand, neck or even uterus/womb (may result in sickness or on the contrary, super power!!! ). Thus, we have ruqyah using Quranic verses (Al Fatiha, etc.)

I don't know any jinn to ask that question

On a more serious answer, I haven't found solid (sohih) literature on how they do it. Just know that there are hadeeth (whether direct or non direct/implied) that relates to the jinns inhibiting the human body, or a part of the body.

With regards to the dua before intercourse (apparently my keyboard dictionary doesn't have this word for swype typing), iirc the fadilah is that the child, should it end up with "fertilization", would be protected from syaiton. So it's not really the womb that is protected.

About ruqyah, there is an added advantage for one who never asked to be ruqyah-ed (I guess the English word would be, excorcized? But sounds cheezy). It is allowed and you don't sin. But one possible fadilah will escape you as per the following extract from a lengthy hadeeth:

Kemudian dikatakan kepadaku ini adalah umatmu, dan bersama mereka ada tujuh puluh ribu orang masuk surga tanpa hisab dan tanpa adzab”.

Kemudian beliau shallallahu ‘alaihi wa sallam bangkit dan bergegas masuk ke dalam rumahnya. Maka para shahabat mulai membicarakan siapakah mereka itu. Di antara mereka ada yang mengatakan, ‘Mungkin mereka adalah orang-orang yang menjadi shahabat Rasulullah’. Ada lagi yang mengatakan, ‘Mungkin mereka adalah orang-orang yang dilahirkan dalam lingkungan Islam, sehingga mereka tidak pernah berbuat kesyirikan’. Dan ada di antara mereka yang menyebutkan kemungkinan lainnya. Maka Rasulullah shallallahu ‘alaihi wa sallam keluar dan menemui mereka dan menjelaskan, “Mereka adalah orang-orang tidak meminta diruqyah, tidak meminta diobati dengan cara kai (menempel luka dengan besi panas), tidak melakukan tathayur, dan mereka adalah orang-orang yang bertawakal kepada Rabb mereka” (HR. Bukhari 5705, 6541 dan Muslim 220)



Source : https://muslim.or.id/5358-masuk-surga-tanpa...anpa-adzab.html

ok, new topic...

anyone can verify the quoted below? got from whatsapp group (not an Islamic group, just normal kengkawan group). It basically says that the great Muslim scientist Avicenna is not a Muslim at all.

I remember when I was young, got told by a teacher that actually Avicenna said that booze (alcohol, beer, etc.) is halal for him as it allows him to be creative and produce the literatures. Now, the ruling of someone changing the laws (i.e. making haram things halal, or vice versa), is that he may have forsaken his faith and become kafir (I say may since the judgment requires detailed analysis of his actions, motives, level of knowledge, etc.)... So if that were true, it means Avicenna may have already forsaken Islam.

Again, source is in Bahasa Indonesia. Anyone with better comprehension of this language can pls share the summary here...

QUOTE:
Salah satu pengkabutan sejarah yang telah berhasil oleh Syiah...
Saatnya kita kembali belajar kpd ulama salaf..

Apa kata mereka tentang Ibnu Sina..

TAHUKAN ANDA SIAPA IBNU SINA?

》Orang-orang memberi nama:
▪ Sekolah "Ibnu Sina"
▪ Apotek "Ibnu Sina"
▪ Rumah Sakit "Ibnu Sina"
▪ Kamar "Ibnu Sina"
▪ Laboratorium "Ibnu Sina"

● Tahukah mereka, siapakah Ibnu Sina?

🌰 Mari Menelisik Hakikat Ibnu Sina ?

📄 Ibnu Sina - semoga Allah tidak meridhoinya- memiliki nama Al Husein bin Abdillah.Dia sangat terkenal di bidang kedokteran sehingga banyak orang memujinya dan mengabadikan namanya di bidang kesehatan, bahkan menisbahkannya dengan Islam.Padahal dia memiliki kesesatan yang Islam berlepas darinya.

📄 Bacalah keterangan ulama Salafy, yang dulu maupun sekarang, tentang siapa Ibnu Sina.Agar kita tidak ikut latah memuji dan menyandarkan namanya sebagai "Dokter Islam".

🌰 Syaikhul Islam Ibnu Taimiyyah rahimahullah berkata: "Ibnu Sina itu seorang Syiah Rafidhah dari sekte Qaramithah.Dia mencela dan merendahkan kehormatan para shahabat radhiyallahu anhum.

🌰 Ibnul Qayyim Al Jauziyyah rahimahullah berkata dalam Ighasatul Lahafaan 2/267 : "Imamnya orang-orang yang menyimpang itu adalah Ibnu Sina."

🌰 Ibnu Sholah rahimahullah dalam Fatawa Ibnu Sholah 1/209 berkata: "Ibnu Shina itu termasu salah satu setan dari kalangan setan manusia."

🌰 Adz Dzahabi rahimahullah berkata dalam Mizanul I'tidal: "Aku tidak mendapati riwayat ilmu sedikitpun dari Ibnu Sina.Kalaupun ada ilmu darinya, tidak boleh mengambilnya.Hal itu karena dia seorang ahli filsafat, plagiat, dan sesat."

🌰 Ibnu Hajar Al Asqolani rahimahullah mengomentari ucapan Adz Dzahabi di atas, mengatakan: "Semoga Allah tidak meridhoi Ibnu Sina."

🌰 Asy Syaikh bin Baaz rahimahullah berkata: "Tidak layak bagi kaum muslimin menamai suatu tempat dengan nama Ibnu Sina atau Al Farabi, semoga Allah menjelekkannya." ( Al Fawaid Al Jaliyyah karya Az Zahrany hal 37)

🌰 Asy Syaikh Shalih Al Fauzan

❓❓Syaikh yang mulia, semoga Allah memberi kebaikan kepadamu. Apa pendapatmu kepada orang yang memuji Ibnu Sina dan menjadikan dia termasuk salah satu ulama kaum muslimin, semoga Allah membalas kebaikan kepadamu ?

***Jawaban :

Orang yang mengatakan hal tersebut berada diantara dua kemungkinan.

1⃣ Kemungkinan pertama dia adalah orang jahil dan tidak mengetahui keadaan Ibnu Sina, maka orang yang demikian tidak pantas untuk berbicara tentang Ibnu Sina, yang menjadi kewajibannya adalah diam.

2⃣ Kemungkinan kedua,dia mengetahui keadaan asli Ibnu Sina, tahu kekafirannya, menetapkan hal tersebut, maka hukumnya sebagaimana Ibnu Sina dihukumi.Kita berlindung kepada Allah dari hal yang demikian.Karena dia mengetahui dan menetapkan kekafiran Ibnu Sina namun dia malah memberikan pujian kepadanya.Sungguh ini perkara yang berbahaya.Akan tetapi, sebagian orang yang memberikan pujian kepada Ibnu Sina, karena penghormatan bahwa dia seorang dokter saja.Ini merupakan perkara dunia. Dia (Ibnu Sina) seorang dokter dan diantara orang kafir ada dokter yang lebih ahli dari pada Ibnu Sina, maka mengapa hanya mengkhususkan pujian kepada Ibnu Sina?
Mereka katakan: "Karena Ibnu Sina itu menyandarkan dirinya kepada Islam, sehingga ini merupakan kebanggaan untuk Islam."
Maka kita katakan: "Islam berlepas diri darinya dan Islam tidak membutuhkannya."

Kesimpulannya, Ibnu Sina tidak layak untuk dipuji dan diberi rekomendasi, karena dia seorang penganut Syiah Bathiniyyah , ahli filsafat, atheis dan menyatakan bahwa alam ini ada dengan sendirinya." (At Ta’liiq Al Mukhtashar ‘alal Qasiidah An Nuuniyah 3/ 1328)

⛔ Maka, berhentilah memuji Ibnu Sina.Islam tidak butuh sesuatu dari Ibnu Sina.

و الله الموفق
➰➰➰➰➰➰➰

🌻 diterjemahkan dengan penambahan dan pengurangan oleh Abu Mas'ud Jarot عفا الله عنه dari sebuah artikel berjudul "حقيقة ابن سينا" di Grup الملتقى السلفي بالداخلة

🏡 FORUM SALAFY SURABAYA

END-QUOTE

thanks for reminder.
kind to think of it, this is also the stand i took when got confronted by one of those guys (i cant remember what they are called, but they go around saying this and that about this ustadz or that ulama, etc. saying they are dangerous and cannot be trusted, but stopped shy from declaring them kafir). Heh... dont know how I took different stand this time lar... let my guard down may be because I have heard of it before.

Basically, I said that I am not at the level of knowledge to yet have to take note of such issue and take action. I am still studying from the ground level and therefore will only learn from the "safe" ulama. In my mind this will include the four Imam Madzhab, Ibn Taimiyah, Ibnul Qayyim, Ibn Katheer, Bukhari & Muslim and the other experts on hadeeth of past era, Al Albani, Bin Baaz, Utsaimin, and Jibreen. I have no credibility and it is not my right to participate in such action to warn muslims against certain ulama/ustadz... (like a biologist claiming a physician wrong, eh?)

However, to elaborate more on the matter of "menghalalkan yang haram and vice versa" without naming anyone (i mean, we are just discussing the principle here, or the action, not the person/people) as follows:

QUOTE

Ibnu Taimiyyah rahimahullah berkata :
والإنسان متى حلّل الحرام المجمع عليه ، أو حرم الحلال المجمع عليه ، أو بدَّل الشرع المجمع عليه : كان كافراً مرتدّاً باتفاق الفقهاء ، وفي مثل هذا نزل قوله تعالى – على أحد القولين (وَمَنْ لَمْ يَحْكُمْ بِمَا أَنْزَلَ اللَّهُ فَأُولَئِكَ هُمُ الْكَافِرُونَ) [ المائدة 44 ] ، أي : هو المستحل للحكم بغير ما أنزل الله
“Dan seseorang ketika menghalalkan yang haram yang telah disepakati keharamannya, atau mengharamkan yang halal yang telah disepakati kehalalannya, atau mengganti syari’at yang telah disepakati[1] : maka ia kafir lagi murtad dengan kesepakatan fuqahaa’. Dan yang semisal dengan ini adalah tentang firman Allah ta’ala – menurut salah satu dari dua pendapat - : ‘Barangsiapa yang tidak memutuskan menurut apa yang diturunkan Allah, maka mereka itu adalah orang-orang yang kafir’ (QS. Al-Maaidah : 44), yaitu orang yang menghalalkan untuk berhukum dengan selain yang diturunkan Allah” [Majmuu’ Al-Fataawaa, 3/267].

Namun,..... banyak orang salah paham dalam permasalahan istihlaal ini, sehingga mengkonsekuensikan penerapan dan penghukuman yang tidak tepat.

Ibnu Taimiyyah rahimahullah berkata :
والاستِحلالُ : اعتِقادُ أنها حلالٌ له
“Istihlaal adalah i’tiqaad (keyakinan) bahwasannya sesuatu itu halal baginya” [Ash-Shaarimul-Masluul, 3/971].

Ibnul-Qayyim rahimahullah berkata :
فإنَّ المُستحلَّ للشيء هو : الذي يفعله مُعتقِداً حِلَّه
“Karena sesungguhnya orang yang menghalalkan sesuatu adalah orang yang melakukannya dengan keyakinan akan kehalalannya” [Ighaatsutul-Lahfaan, 1/382].

Ibnu ‘Utsaimiin rahimahullah berkata :
الاستحلال هو : أن يعتقد الإنسان حلّ ما حرّمه الله ... وأما الاستحلال الفعلي فيُنظر : لو أن الإنسان تعامل بالربا , لا يعتقد أنه حلال لكنه يُصرُّ عليه ؛ فإنه لا يُكفَّر ؛ لأنه لا يستحلّه
“Istihlaal adalah seseorang yang meyakini kehalalan apa-apa yang diharamkan Allah….. Adapun istihlaal dalam perbuatan (fi’liy), maka dilihat : Seandainya seseorang yang bermuamalah dengan riba tanpa berkeyakinan bahwasannya ia halal, akan tetapi ia terus-menerus melakukannya; maka ia tidak dikafirkan, karena ia tidak menghalalkannya” [Al-Baabul-Maftuuh, 3/97, pertemuan ke-50, soal no. 1198].[2]
Dari sini dapat kita ketahui bahwa istihlaal adalah masalah hati, karena hakekatnya merupakan i’tiqaad (keyakinan) akan halalnya sesuatu. Dikarenakan masalah hati, maka ia tidak diketahui kecuali dengan adanya kejelasan yang berasal dari pelakunya.

END-QUOTE

thanks... but TLTR
can summarize ala /k or not?

my take:

wahabi is described in the TLTR link (which I requested summary for). i have come accross other literature that there are two wahabi, the one people are arguing against nowadays, and one of old times (waaaay back) which the ulama of those times declared were in the wrong.

salaf, I believe means the first three generations (the sahabat, those that learn from the sahabat - or tabi-in, and those that learn from the tabi-in)

sufi - i don't know enough to say anything

bidaah, literally means something new. but when in context of syara', bidaah means (and this is my own understanding, mind you) something not prescribed in the time of salaf that is related to this religion of ours. so, taking medicine is a bidaah in the literal meaning, but is not bidaah in the syara' meaning (because it is not related to the religion).

syiah and sunni, are two of the biggest ummah. Sunni is the mainstream "aliran" of Islam, practiced in many places including here in Malaysia. Both sunni and syiah claim they worship Allah, claim Muhammad Shalallaahu 'alaihi wa sallam as the final prophet (and by consequence, both follow the quran and hadeeth). however, they have differences. Sunni claims syiah does not believe the quran we have is authentic or complete. Sunni also claim that syiah have different narrators and chain of trusted narrators for hadeeth. Sunni also claim that syiah proclaimed Ali as the rightful caliph (instead of Abu Bakar) and so on... for fairness sake i can only say what the sunni claims, since I am brought up as sunni myself. but like previous post, since i still have so much to learn, i have no authority to declare which is right and which is wrong.

That's because for ibadah, you need dalil. No ibadah can be done (i.e. It would be haram to do) without a dalil. Because this religion is decreed by Allah (and by consequence, decreed via sunnah), therefore something is not part of the religion if it is not decreed. A simple example is fasting in Ramadhan, it was not done before the ayat came (i.e. The decree by Allah).

On the other hand, what is not ibadah (termed by some scholars as "muamalah") is halal until there is dalil that forbids it.

So, reading the yasin is an ibadah, right? That is why there are people who ask where is the dalil.

I beg to differ.

as before, for ibadah, the principle is you have to have the basis (dalil) that allow you to do it, before you can do it. so basically, takde dalil maka haram buat ibadah tu. otherwise, the consequences of "tiada dalil melarang maka hukumnya harus" is that we can do any variation to the ibadah we do. so if a sect performs prayer by jumping up and down, then it would be allowed because no dalil forbids it. or that you read the Quran backwards can be considered ibadah. and so on.

you can see a lot of examples of this principle through out the whole dakwah period of our Nabi SAW. the five daily prayers were not practiced before the ayat was revealed. (although the prayer itself was established from religions past). the fasting month went on without fasting before the ayat came. there was no zakat, and so on... there was only tauhid in the beginning- to believe in one God: Allah - and its implications.

some ulama will quote this:

فَاعْلَمْ أَنَّهُ لَا إِلَهَ إِلَّا اللَّهُ وَاسْتَغفِرْ لِذَنبِكَ

“Ketahuilah bahwa tidak ada sesembahan yang berhak disembah selain Allah dan mintalah ampunan untuk dosamu” (QS. Muhammad: 19)

"So know, [O Muhammad], that there is no deity [worthy to worship] except Allah and ask forgiveness for your sin"

where فَاعْلَمْ is also interpreted as you have to have the knowledge, the basis, the dalil... before you can "worship" (or basically, beribadah)...

Also the hadeeths:

Juga didukung dengan hadits ‘Aisyah radhiyallahu ‘anha, Nabi shallallahu ‘alaihi wa sallam bersabda,

مَنْ أَحْدَثَ فِى أَمْرِنَا هَذَا مَا لَيْسَ مِنْهُ فَهُوَ رَدٌّ

“Barangsiapa membuat suatu perkara baru dalam agama kami ini yang tidak ada asalnya, maka perkara tersebut tertolak.” (HR. Bukhari no. 20 dan Muslim no. 1718). Dalam riwayat lain disebutkan,

مَنْ عَمِلَ عَمَلاً لَيْسَ عَلَيْهِ أَمْرُنَا فَهُوَ رَدٌّ

“Barangsiapa melakukan suatu amalan yang bukan ajaran kami, maka amalan tersebut tertolak.” (HR. Muslim no. 1718).

(Read more https://rumaysho.com/3119-hukum-asal-ibadah...ada-dalil.html)

the words "tidak ada asalnya" and also "bukan ajaran kami" points to having a basis/dalil. the above hadeeths are usually discussed with regards to bid'ah (in religion), but they are of the same principle and closely related.

this is what i go by with regards to ibadah. hence i don't do doa after the prayer because honestly, i haven't found the dalil. i do dzikir, because i have found the dalil.

the principle "tiada dalil melarang maka humumnya harus" (well, actually, hukumnya boleh) applies to anything outside of the ibadah. if there was no word to stop us, we would have been eating khinzir, drinking booze, etc. on the other hand, we are free to interact with others, until the limit set by Islam: mendekati zina. we are free to do business as we like as long as we don't cross the rule: no riba. we can use medicine to cure our sickness, because despite there is "ruqyah" Islam does not forbid us to take medicine.

and so on.

wallaahu a'lam.

This post has been edited by abu.shofwan: Sep 23 2016, 08:29 AM

doing an ibadah at a specific time or place or method, also requires dalil.

the timing for our five daily prayer is not specified in the Quran. so without dalil (which came in the form of sunnah/hadeeth/atsar), how do we know the timing? only the general timing is given in Quran.

this principle is applied to reading yasin (the "what" ibadah) on thursday night (the "when" of the ibadah). reading the yaasin by itself is ibadah, because there is dalil that encouraged us to read (i.e. allow us to read) the Quran - or any part of it. however, the "when" is the one without dalil. like another had stated, on the night before friday (which is already Friday, in Islamic calculation of days) there is only dalil of reading Al Kahfi.

on sunat and wajib, not really sure what you mean. but here's my take of it.

Ibadah sunah and wajib bears many resemblance but also can have a lot of differences. really have to look at it case by case. for example, the nawafil/sunnah prayers, we have the "sholat sunat mutlak" - praying two rakaat at any time other the forbidden times. the way we pray (how we do takbir, ruku', sujud, etc.) is the same, but the timing is different with the five daily prayers.

the sodaqoh sunah and sodaqoh wajib (a.k.a. zakat) also have similarities and differences. you can give money under both types, but how much is different (one is free-will, the other is 2.5%) and the timing also can be different (zakat needs one year to complete).

on the side of dalil, the sunat will have a more "general" dalil or instruction. the wajib, will have more specific instruction related to timing, numbers, etc. like reading the yaasin - it goes under the general instruction to read the Quran.

and of course, being sunat, you don't sin if you don't do it.

wallaahu a'lam.

not sure if i am knowledgable enough to say for sure. but at least i can share what i have understood and hope others will chime in also.

at the grass-root level, ibadah needs dalil that describes it: how it's done (i.e. the movement for prayers, the recitation, etc.), when it's done (but the dalil may be general also, meaning it can be done anytime), the number (2 for subuh, 3 for maghrib, 4 for others), and so on.

in the case of yaasin, it is not reading the yaasin that has issues. rather it is reading the yaasin (and only yaasin) on the night before friday. this means, there is direction to read a specific surah (the yaasin) on a specific time (night before friday). no one can specify the specifics but the owner of this religion: Allah - which is done through either the Quran or the Sunnah. if we "make our own rules" with regards to ibadah by determining the specifics of something general (remember, reading yaasin has a "general" dalil that does not prescribe the timing), it means we are taking over the part of Allah as the One that sets the rules. (I believe this principle also extends to the making of law/constitution/regulation - but this is something i have not yet learned).

why not we read the 18th surah instead, since we have dalil of reading it on Friday (Thursday night after maghrib is already counted as Friday in Islamic calendar calculation). why must it be replaced with Yaasin?

Or from another perspective, why must we read Yaasin (and not other surah) on the night of Friday and not on the night of (say for example) Thursday?

If we read the Quran regularly every night and it just so happens that we reach Yaasin on the night before Friday, then it is acceptable since we are not specifically establishing that Yaasin should be read at that time.

for the right time to do doa, i have found that there is hadeeth that recommends us reciting doa during our sujud and also after reading the tahyat/tasyahud at the end, before the salaam.

and let's not forget, between two sujud - we actually recite doa "allaahumma firliii..."

more on it here:
https://islamqa.info/en/7886

for doa before salaam:

Dalam hadits dari Abu Hurairah bahwa Rasulullah shallallahu ‘alaihi wa sallam bersabda,

إِذَا تَشَهَّدَ أَحَدُكُمْ فَلْيَتَعَوَّذْ بِاللَّهِ مِنْ أَرْبَعٍ مِنْ عَذَابِ جَهَنَّمَ وَعَذَابِ الْقَبْرِ وَفِتْنَةِ الْمَحْيَا وَالْمَمَاتِ وَمِنْ شَرِّ الْمَسِيحِ الدَّجَّالِ ثُمَّ يَدْعُو لِنَفْسِهِ بِمَا بَدَا لَهُ

“Jika salah seorang di antara kalian bertasyahud, maka mintalah perlindungan pada Allah dari empat perkara yaitu dari siksa Jahannam, dari siksa kubur, dari fitnah hidup dan mati dan dari kejelekan Al Masih Ad Dajjal, kemudian hendaklah ia berdoa untuk dirinya sendiri dengan doa apa saja yang ia inginkan.” (HR. An Nasai no. 1310. Syaikh Al Albani mengatakan bahwa hadits ini shahih)

which is a further elaboration of:

Dari Abu Hurairah, Rasulullah shallallahu ‘alaihi wa sallam bersabda,

إِذَا فَرَغَ أَحَدُكُمْ مِنَ التَّشَهُّدِ الآخِرِ فَلْيَتَعَوَّذْ بِاللَّهِ مِنْ أَرْبَعٍ مِنْ عَذَابِ جَهَنَّمَ وَمِنْ عَذَابِ الْقَبْرِ وَمِنْ فِتْنَةِ الْمَحْيَا وَالْمَمَاتِ وَمِنْ شَرِّ الْمَسِيحِ الدَّجَّالِ

“Jika salah seorang di antara kalian selesai tasyahud akhir (sebelum salam), mintalah perlindungan pada Allah dari empat hal: (1) siksa neraka jahannam, (2) siksa kubur, (3) penyimpangan ketika hidup dan mati, (4) kejelekan Al Masih Ad Dajjal.” (HR. Muslim no. 588).

Read more https://rumaysho.com/8684-sifat-shalat-nabi...ahud-akhir.html

Can translate? Honestly speaking, I am not confident of my jawi proficiency...