I hit a man back when he hit me.
What made him hit you first?
I told him that he was wrong, then he punched me, so I punched him back.
The man punching you just because you said he wrong was incorrect. In this situation, I think defending yourself is the right choice.
I have to be ready in case someone attacks me.
I agree that you need to be ready. Violence should not be seeked out, but there comes a time where you should protect yourself and your loved ones.