The utter beauty and freedom of the Gospel of Christ (as compared to the chains of Roman Catholicism) is that penance is neither necessary nor possible.
"But now apart from the Law the righteousness of God has been manifested, being witnessed by the Law and the Prophets even the righteousness of God through faith in Jesus Christ for all who believe; for there is no distinction; for all have sinned and fall short of the glory of God, beiing justified as a gift by His grace through the redemption which is in Christ Jesus;..."
Notice, no penance, no confessional, no priesthood and certainly no pope involved. Rome has manufactured its own self-righteousness which is another gospel...from the darkness. We invite those enslaved to the Roman cult to come out into the light of Christ alone...if you can.
I admire your constancy, sir. It is a gift to be so wrong so often, in so many ways. Do you have your Bible handy?
Acts 7: 51 "You stiff-necked people, uncircumcised in heart and ears, you always oppose the holy Spirit; you are just like your ancestors. 52 Which of the prophets did your ancestors not persecute? They put to death those who foretold the coming of the righteous one, whose betrayers and murderers you have now become. 53 You received the law as transmitted by angels, but you did not observe it." 54 When they heard this, they were infuriated, and they ground their teeth at him.
But on to penance. The precedence is set in:
Numbers 5: 6 "Tell the Israelites: If a man (or a woman) commits a fault against his fellow man and wrongs him, thus breaking faith with the LORD, 7 he shall confess the wrong he has done, restore his ill-gotten goods in full, and in addition give one fifth of their value to the one he has wronged. 8 3 However, if the latter has no next of kin to whom restoration of the ill-gotten goods can be made, the goods to be restored shall be the LORD'S and shall fall to the priest; this is apart from the atonement ram with which the priest makes amends for the guilty man.
Leviticus 4-7 is even more explicit - with penance instructions for individual men, for priests, and for princes.
And what does the NT bring? Matthew 5: 6 23 Therefore, if you bring your gift to the altar, and there recall that your brother has anything against you, 24 leave your gift there at the altar, go first and be reconciled with your brother, and then come and offer your gift. 25 Settle with your opponent quickly while on the way to court with him. Otherwise your opponent will hand you over to the judge, and the judge will hand you over to the guard, and you will be thrown into prison. 26 Amen, I say to you, you will not be released until you have paid the last penny.
The Lord's Prayer tells us to forgive those who have transgressed against us, and Matthew 18 tells us to forgive our brother in essentially unlimited fashion. Therefore, we are instructed to do penance to our brethren whom we wronged, and to forgive others their penance towards us.
Penance due God and penance due our fellow men.