Yes, it is found in Scripture.
“Whose sins you shall forgive, they are forgiven them, whose sins you hold bound shall be held bound.” Paraphrasing —
Whose sins you shall forgive, they are forgiven them, whose sins you hold bound shall be held bound.
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That... has nothing to do with doing penance. That’s pure grace through faith, not doing works to work off sin.
Unless you define it differently.
Besides, God overrides it with THIS promise......
1 John 1:9 If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.
So explain to me how a priest can override God's promise.