Jerome’s Latin translation of the Greek metanoeo / μετανοεω was a mistake. The Latin was “do penance” and developed into doing external deeds that the priest said, like crawl up steps and say 100 hail Mary’s or give money to the poor or the church for forgiveness. That is wrong. “Repent” is an internal turning from sin to God that includes a godly sorrow that leads to change and salvation.

Also, Jerome’s translation from Greek into the Latin word for justification was wrong also. (the Greek is: “the count righteous / just / right” but the Latin had more the idea of “to make righteous / just / right”. These 2 mistakes in translation and relying upon them (rather than the original Greek) for centuries is just one of the problems of what later became the Roman Catholic Church.

This is a good explanation:

Actually, “TheDen,” you omitted a very…