This is what Yogananda said
Why forgive one who wrongs you? Because if you angrily strike back you misrepresent your own divine soul nature — you are no better than your offender. But if you manifest spiritual strength you are blessed, and the power of your righteous behavior will also help the other person to overcome his misunderstanding.
The desire for vengeance is a karmic cage that imprisons both individuals and cultures into enduring suffering. If you carry a strong enough desire for vengeance into your after-life, you will have to reincarnate in circumstances where you can fulfill that desire.
But then your “victim” will have to get his chance for vengeance. On and on goes this terrible cycle until you can say “Enough, let God, not me be the judge.” You will pass a great test of karma if you truly pray that God forgive your adversary.
The latter half is from Ananda.org. He was also a direct disciple of Yogananda
He did write it properly. There are a few deeper reasons for it. But that is not for public discussion.
Bhavin