Is the punishment of the oppressor limited to the act he committed? Is it permissible to strike someone who insults me? What is the ruling if I strike a person who threw small stones at me as a joke after I warned him, or if I strike an ill-mannered, sharp-tongued person after he verbally abused me?

It is advisable to avoid dealing with such individuals as much as possible. If dealing with them becomes necessary, it should be done with justice and reciprocity, as Allah Almighty commanded: "So whoever commits aggression against you, then aggress against him in like manner as he aggressed against you," and "And if you punish, then punish with the like of that with which you were afflicted."

Reciprocity here means not exceeding the extent of the insult. Cursing twice for one curse is usury (riba) and one of the gravest major sins is for a person to unduly disparage the honor of a Muslim.