Silsilah as-Sahihah 90 — How to distinguish good and evil

Sayyiduna Abdullah (may Allah be pleased with him) narrates that a man said: O Messenger of Allah! When I do a good deed, how will I know that I have done good? The Prophet (peace and blessings be upon him) said: "When you hear your neighbors saying that you have done good, then you have done good; and when you hear them saying that you have done evil, then you have done evil."