Man's depravity, as a result of the Fall, is total. All men are born into this world spiritually dead, blind, and deaf to the things of God; the sinner's heart is desperately corrupt. His will is not free; it is in bondage to his evil nature. Therefore, he has lost his ability to choose good over evil in the spiritual realm. It takes more than the Spirit's assistance to bring the sinner to Christ - it takes regeneration by which the Spirit makes the sinner alive and gives him a new nature. Faith is not something man contributes to salvation but is itself a part of God's gift of salvation - it is God's gift to the sinner, not the sinner's gift to God.
Psa 51:5; 58:3; Isa 53:6; 64:6; Jer 17:9; John 3:3; 8:44 Rom 3:10-12, 5:12; Eph 2:2-3; 1 Cor 2:14