REPENTANCE - Literally, "a change of mind" or attitude, and thus of behavior. God is the author of repentance, which is an integral part of baptism, confession, and ongoing spiritual life. Repentance is not simply sorrow for sins but a firm determination to turn away from sin to a new life of righteousness in Jesus Christ. (Matt. 4:17; 2 Pet. 3:9; 1 John 1:9.)
Repentance is more than regret or contrition; it requires a fundamental change of life. Christ tells us that the path for approaching the Kingdom of God is repentance. A more accurate translation of Matthew 4:17, is Keep repenting for the Kingdom is at hand; in other words, not once but continually. We must continually re-direct ourselves, until we achieve life's objective union with God as such repentance is a mystery.
Repentance is not legalistic; i.e. if a penance is given during confession by the spiritual confessor, this will be purely for therapeutic reasons, whose aim is to clear the nous and the heart from sin.