This word means “to be brought to life.” It can be applied to the soul (John 5:21; 6:63; Eph. 2:1, 5; Col. 2:13) and also to the human body (Rom. 4:17; 8:11; 1 Tim. 6:13)—even to the Lord’s body (1 Peter 3:18).
As to the soul, God works upon the elect in sovereign power to bring spiritually dead persons to life by imparting a divine life to them (Eph. 2:1, 5a). As a result, when a person is thus awakened, he is given spiritual faculties whereby he is able to hear and understand spiritual communications from God—i.e. the gospel. Upon believing the gospel and resting in faith on the finished work of Christ, the “quickened” soul is “saved” (Eph. 2:5b, 8). Thus, quickening refers to the same action of the Spirit as being “born again,” but viewed from a different perspective:
New birth views man’s condition as having a corrupted nature, and therefore, in need of a new life and nature, which God imparts by His sovereign power.
Quickening views man’s condition from the perspective of being dead, and thus needing new life from God, which quickening conveys.
Without God sovereignly working in this way in souls, no one would believe the gospel, because prior to quickening, men are spiritually unconscious (being dead), and thus have no capability of hearing and responding to the call of God. (See Born Again and Freewill.)
As to our bodies, Romans 8:11 states that the believer’s body will be quickened, and thus glorified by the Holy Spirit. It does not tell us when this will happen, but we know from other passages that it will be at the Rapture (1 Cor. 15:51-56; Phil. 3:21).