Are you a property agent working for a real estate agency? if not, why the need to file tax?

This is neither employment income nor business income, you can say you are just doing a favor for a friend and he gave you some monetary gift, which are totally off the book, how is this taxable?

Why don't you do us all a favor by giving the exact reference or link that shows that this is indeed classified as an "income" and taxable. Else you are just another keyboard warrior who has no idea what he's talking about.

To me, this is no difference from money inherited from your rich parent, or your rich uncle suddenly decided to give you a large sum of money, which I'm pretty sure are not taxable