Sunan An-Nasa'i

It was narrated from Abu Musa that the Prophet said:""Every Muslim must give charity."" It was said: ""What if he cannot find (anything to give)? ""He said: ""Let him work with his hands and benefit himself and give in charity."" It was said: ""What if he cannot do that?"" He said: ""Let him help someone who is in desperate need."" It was said: ""What if he cannot do that?"" He said: ""Let him enjoin good."" It was said: ""What if he cannot do that? He said: ""Let him refrain from doing evil, for that is an act of charity