Should a person continue to advise an evildoer?

Question 5: Does enjoining Ma`roof (that which is judged as good, beneficial, or fitting by Islaamic law and Muslims of sound intellect) and forbidding Munkar (that which is unacceptable or disapproved of by Islaamic law and Muslims of sound intellect) continue to be obligatory as long as the person who does the Munkar is insisting on it, or it is enough to explain the ruling to them only one time?

Answer: You should continue advising whoever commits Munkar until you think that doing so alone is not enough… read more here.