Anger is short-lived in a good man.

The proverb presents brief anger as consistent with good character. A decent person may become angry, but does not stay angry for long.

Its emphasis is on how quickly anger passes, not on never feeling it. A moment of anger need not define a person's character.

Use it to distinguish a passing angry reaction from a lasting disposition, or to suggest that a person's anger is likely to subside. It does not mean that the initial anger was necessarily unjustified.