2 Cor 1:22

1:22 put his seal on us. An official seal indicated authority or ownership and guaranteed protection (Esth. 8:8; Dan. 6:17; Matt. 27:66; Rev. 7:3). God has sealed us, not with a physical seal of wax, but with the Holy Spirit in our hearts (Eph. 1:13; 4:30). This inward work takes place in a person once, at the time of first becoming a Christian.

guarantee. The Greek word means a deposit or down payment that is part of the total and that guarantees the whole payment will be made. The Holy Spirit is the guarantee of the complete salvation yet to be realized (5:5; Rom. 8:23; Eph. 1:14). We already have heavenly life within us, before we reach heaven (1 Cor. 3:16; Col. 1:27).