One of the best explanations of Repentance I have ever read was by J.I. Packer. I have quoted it in full below. The excerpt is from Rediscovering Holiness by J.I. Packer, published by Regal Books, 2009. The except comes from chapter five.
What is repentance?
What does it mean to repent? The term is a personal and relational one. It signifies going back on what one was doing before, and renouncing the misbehavior by which one's life or one's relationship was being harmed. In the Bible, repentance is a theological term, pointing to an abandonment of those courses of action in which one defied God by embracing what he dislikes and forbids. The Hebrew word for repenting signifies turning, or returning. The corresponding Greek word carries the sense of changing one's mind so that one changes one's ways too. Repentance means altering one's habits of thought, one's attitudes, outlook, policy, direction, and behavior, just as fully as is needed to get one's life out of the wrong shape and into the right one. Repentance is in truth a spiritual revolution. This, now, and nothing less than this, is the human reality that we are to explore.
Repenting in the full sense of the word–actually changing in the way described–is only possible for Christians, believers who have been set free from sin's dominion and made alive to God. Repenting in this sense is a fruit of faith, and as such a gift of God (cf. Acts 11:18). The process can be alliteratively analyzed under the following headings:
1. Realistic recognition that one has disobeyed and failed God, doing wrong instead of doing right. This sounds easier than it actually is. T.S. Eliot spoke the truth when he observed: "Humankind cannot bear very much reality." There is nothing like a shadowy sense of guilt in the heart to make us passionately play the game of pretending something never happened or rationalizing to ourselves action that was morally flawed. So, after David had committed adultery with Bathsheba and compounded it with murder, he evidently told himself that it was simply a matter of royal prerogative and, therefore nothing to do with his spiritual life. So he put it out of his mind, until Nathan's “You are the man!” (2 Samuel 12:7) made him realize, at last, that he had offended God. This awareness was, and is, the seed bed where repentance grows. It does not grow elsewhere. True repentance only begins when one passes out of what the Bible sees as self-deception (cf. James 1:22, 26; 1John 1:8) and modern counselors call denial, into what the Bible calls conviction of sin (cf. John 16:8).
2. Regretful remorse at the dishonor one has done to the God one is learning to love and wanting to serve. This is the mark of the contrite heart (cf. Psalm 51:17; Isaiah 57:15). The Middle Ages drew a useful distinction between attrition and contrition (regret for sin prompted by fear for oneself and by love for God respectively; the latter leading to true repentance while the former fails to do so). The believer feels, not just attrition, but contrition, as did David (see Psalm 51:1-4, 15-17). Contrite remorse, springing from the sense of having outraged God's goodness and love, is pictured and modeled in Jesus' story of the prodigal's return to his father (Luke 15:17-20).
3. Reverent requesting of God's pardon, cleansing of conscience, and help to not lapse in the same way again. A classic example of such requesting appears in David's prayer of penitence (see Psalm 51:7-12). The repentance of believers always, and necessarily, includes the exercise of faith in God for these restorative blessings. Jesus himself teaches God's children to pray “forgive us our sins... and lead us not into temptation” (Luke 11:4).
4. Resolute renunciation of the sins in question, with deliberate thought as to how to keep clear of them and live right for the future. When John the Baptist told Israel's official religious elite: "Produce fruit in keeping with repentance" (Matthew 3:8), he was calling on them to change direction in this way.
5. Requisite restitution to any who have suffered material loss through one's wrongdoing. Restitution in these circumstances was required by the Old Testament law. When Zacchaeus, the renegade Jewish taxman, became Jesus' disciple, he committed himself to make fourfold retribution for each act of extortion, apparently on the model of Moses' requirement of four sheep for everyone stolen and disposed of (Exodus 22:1; Exodus 22:2-14; Leviticus 6:4; Numbers 5:7). An alternative alliteration (as if one were not enough!) would be:
1. discerning the perversity, folly, and guilt of what one has done;
2. desiring to find forgiveness, abandon the sin, and live a God-pleasing life from now on;
3. deciding to ask for forgiveness and power to change;
4. dealing with God accordingly;
5. demonstrating, whether by testimony and confession or by changed behavior or by both together, that one has left one's sin behind.
Such is the repentance – not just the initial repentance of the adult convert, but the recurring repentance of the adult disciple – that is our present theme.
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