שֵׂ֣כֶל אָ֭דָם הֶאֱרִ֣יךְ אַפּ֑וֹ וְ֝תִפאַרְתּ֗וֹ עֲבֹ֣ר עַל־פָּֽשַׁע׃
It is the discretion of a man to be slow to anger, And it is his glory to pass over a transgression.
Rashi on Proverbs
It is good sense for a man to be slow to anger Heb. האריך, like להאריך, to be slow. If he did so, it is good sense for him.
Rashi on Proverbs
and it is his glory that he pass over his retaliations.