Faith is the actualization of the salvation of God. This is expressed by Paul in Romans 1:17 in a twofold way: "from faith unto faith".
In this decision of faith they are saved from death to life. To have faith in God is to believe in Jesus Christ, His Son (John 14:1; 6:29; 8:42; 5:38). And to believe in Jesus Christ is to receive spiritual life. For Jesus is the life (John 5:26; 6:33-35, 38-40, 57-58). "And this is the testimony that God gave us eternal life, and this life is in His Son. He who has the Son has life; he who has not the Son of God has not life" (I John 5:11-12). To have life is to have passed from death to life. "Truly, truly, I say to you, he who hears my word and believes Him who sent me has eternal life; he does not come into judgment, but has passed from death to life" (John 5:24). The one who believes has passed from death to life because he has in the decision of faith also identified himself with the death and resurrection of Jesus Christ. Christ identified Himself with us in death; He entered into our spiritual death on the cross and died physically for us. His death was our death. In faith we accept His death as our death. In faith we identify ourselves with Him in His death. But since God has raised Jesus from the dead, so also are we made alive with Christ. His resurrection was our resurrection. In faith we identify ourselves with Him and His resurrection. To receive life in Christ is to be raised from the dead with Him. To pass from death to life is to have died and been raised with Jesus from the dead. We are now spiritually alive in Him. We have entered into fellowship with God and are now reconciled to God. As the gospel is preached, God exerts His power and men are made alive, raised from the dead.
"Truly, truly, I say to you, the hour is coming and now isWhen the good news of the death and resurrection of Jesus for us is proclaimed, God speaks to men, revealing Himself in Jesus Christ. Those who hear and believe in Jesus are made alive in Him, being raised from the dead. They are reconciled to God (II Cor. 5:20). They are saved from death to life.
when the dead will hear the voice of the Son of God,
and those who hear will live" (John 5:25).
But in the decision of faith men are not only saved from death to life but also from sin to righteousness. To have faith in God is to acknowledge Jesus as Lord. In general, faith is not just belief that certain statements are true but is the commitment of oneself and allegiance to something or someone as one's own personal ultimate criterion of all decisions, intellectual and moral. Saving faith in Jesus Christ is the commitment of oneself to Jesus Christ as one's own personal ultimate criterion ("My Lord and my God," John 20:28). The living person, the resurrected Jesus Christ, not just what He taught becomes in the decision of faith our ultimate criterion. This decision of faith is a turning from false gods (idols) to the living and true God (I Thess. 1:10). Faith in the true God is righteousness. "Abraham believed God, and it [his faith] was reckoned to him as righteousness" (Rom. 4:3). To believe God is to be righteous (Rom. 4:5). To acknowledge Jesus as Lord is to believe God that He raised Him from the dead. (Rom. 4:22-24).
"9 That if you confess with your mouth Jesus as Lord,To believe God that He raised from the dead Jesus who in faith we confess as Lord is to be righteous. Thus, this decision of faith is salvation from sin to righteousness.
and believe in your heart that God raised Him from the dead,
you will be saved;
10 for with the heart man believes unto righteousness,
and with the mouth he confesses unto salvation."
(Rom. 10:9-10; ERS)