The Shaw Pocket Bible Handbook
, Walter A. Elwell, Editor, (Harold Shaw Publ., Wheaton , IL; 1984), p. 355
To repent means to turn. In the N.T. repentance means to turn from sin. We were called by God to turn from sin. In fact, all men everywhere are commanded by God to repent of their sins (Acts 17:30>). God's longsuffering leads us to repentance (2 Pet. 3:9>) as does His kindness (Rom. 2:4>).
There is true and false repentance, "For the sorrow that is according to the will of God produces a repentance without regret, leading to salvation; but the sorrow of the world produces death" (2 Cor. 7:10>).
Sorrowing over and forsaking sin, a wholehearted turning away from all that is evil. This is more than regret or remorse, attitudes that point to sorrow over sin but no more. Repentance was looked for in Old Testament times (Ezek. 14:6>; 18:30>). It was the first item in the preaching of John the Baptist (Matt. 3:1-2>), Jesus (Matt. 4:17>), and the apostles (Mark 6:12>; cf. Acts 2:38>). Beyond repentance, faith is needed. But repentance is indispensable. Sin must be forsaken decisively.