Hastings' Dictionary of the Bible (1898)
CONVER'SION, or turning from one state, pursuit, inclination, or direction to another. Acts 15:3. T. denotes a change of mind or heart which takes place in the sinner when the Holy Spirit convinces him of his sinfulness, persuades him to hate sin and to forsake it, and to lead a life of holy obedience to Christ. Matt 3:8; Luke 3:3; Luke 15:7; Luke 24:47; Acts 5:31; Acts 11:18; Acts 20:21;2 Cor 7:9-10; 2 Tim 2:25; Heb 6:16; Heb 12:17; 2 Pet 3:9.
Conversion is an act of man, while regeneration, or the new birth, is an act of God, but both are produced by the agency of the Holy Spirit, and usually coincide, though not always; for very young children may be regenerated, but cannot, strictly speaking, be said to be converted. The Scriptures describe mankind as alienated from God, as having the understanding darkened, and as dead in trespasses and sins.
Hence the corresponding force and pertinency of the terms by which the change is described; such as created, renewed, Eph 4:23-24, restored to sight, Eph 1:18; Rev 3:18, and raised from the dead. John 5:21, Jud 6:24; Eph 2:1.