The most common word in the Greek New Testament that conveys the idea of "forgiveness" is aphesis, a compound term meaning "to send away from."
Forgiveness is a divine response to human sin, flowing from the loving and merciful disposition of God (Jn. 3:16; Eph. 2:4). Forgiveness is possible because of Christ's death -- an innocent victim who satisfies the demands of divine justice (Isa. 53:11; Rom. 3:21ff).
But forgiveness is granted only to those who submit to God's plan of pardon (Mk. 16:16; Acts 2:38; 22:16; 1 Pet. 3:21). Man's obedience merits nothing (Eph. 2:8-9). Forgiveness is neither deserved nor earned (Mt. 18:21ff); it is, however, conditional (Heb. 5:8-9).
The spirit of forgiveness must also be present among men. Though no man has the absolute power to forgive sins (see Mk. 2:7) -- Roman Catholic claims to the contrary notwithstanding -- we must always cultivate a merciful spirit, willing to extend pardon to any penitent transgressor (Lk. 17:3). Judgment will be without mercy to him who shows no mercy (Jas. 2:13; cf. Mt. 6:12; 18:32-35).