There comes a time in everybody's life when [one must take a] stand for something. This is a possibility. "To take a stand for/against" is a phrasal verb meaning to assert one's defense for/against something. You can also say, "There comes a time in everybody's life when one must stand up for something.

There comes a time in everybody's life when crime appear he have to stand for the justice. I dont't know if the sentence is grammatical or not. I need some help too : )

...when "they must stand for something"