Question:Do we have to do penance? If we sin and we ask for forgiveness is it enough or do we need someone to give us a penance?
Penance is a Roman Catholic concept which is not found in the Bible. If we stayed with the actual definition of the word, it means "repentance or remorse over past conduct" and that is something taught in the Bible. But in Roman Catholic tradition penance is divided into three parts: contrition (or sorrow) over sin, confession of sin to a priest, and satisfaction though acts of penitence (usually prayers, fasting, or acts of charitable works).
What God teaches is that when we realize that we have done wrong, we sorrow over our failure. "For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death. For observe this very thing, that you sorrowed in a godly manner: What diligence it produced in you, what clearing of yourselves, what indignation, what fear, what vehement desire, what zeal, what vindication! In all things you proved yourselves to be clear in this matter" (II Corinthians 7:10-11). That sorrow causes us to change our behavior (repent) and that repentance is seen in our new behavior.
In order to gain forgiveness for sin, God teaches that we must admit our wrongs to Him. "If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (I John 1:9). The confession of sin is to God and not some earthly man. That is because it is God whom we offended, thus only God can release (forgive) us of our debt due to our sin. Christians do not have a mediator between themselves and God. Every Christian is a priest and has the right to approach God directly. "You also, as living stones, are being built up a spiritual house, a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ" (I Peter 2:5).
There is mention of confessing faults to each other. "Confess your trespasses to one another, and pray for one another, that you may be healed. The effective, fervent prayer of a righteous man avails much" (James 5:16). But once again, there is no mention of going to a priest because all Christians are priests. The purpose of telling fellow Christians of our sins is to ask them to pray for us and with us as we seek God's forgiveness. We can see this when Simon's sin was pointed out to him. He asked Peter, "Pray to the Lord for me, that none of the things which you have spoken may come upon me" (Acts 8:24). The point is that any Christian is to do this for any other Christian.
But the acts of penitence are not found in the Scriptures. Sins do carry their own consequences, for which we must often suffer. But prayers and doing good for our fellow men are not acts of punishment, but a privilege. They are something we always do and not in response to our own sins. God tells governments to punish wrong doers (Romans 13:4) and parents are to discipline their children (Hebrews 12:7-9), but God does not tell Christians to assign to fellow Christians acts designed to gain the forgiveness of God.