Hadith 18720
It is narrated from Hazrat Harmalah (may Allah be pleased with him) that once I presented myself before the Holy Prophet (peace and blessings be upon him) and said, "O Messenger of Allah! Advise me." The Holy Prophet (peace and blessings be upon him) said, "Fear Allah, and when you attend a gathering and then leave from there, if you hear something good, act upon it, and if you hear mention of something bad, then leave it."