Although it is a very common conception in contemporary Evangelicalism that we're “born again” through faith, the bible actually teaches the very opposite: that we have faith by being born again. Being “born again,” or being given a new, spiritual life, is a concept that comes from the Old Testament book of Ezekiel, where God promises to give new, living hearts of flesh to those who were stone dead, with the result that they would then believe in him, obey him, delight in his laws (Ezek. 36:26-27). Then, in the New Testament, Jesus expands on this theme: in John 3:1-21, he tells Nicodemus that he cannot “see” the Kingdom of God, that is, he will have no understanding of spiritual things, unless he is first “born again”. This is why John had said earlier that everyone who “received” Jesus, that is, embraced him in faith, had not been born of their own will or efforts, but of God (John 1:11-13). In other words, when God gives us a new birth, then we immediately respond by believing and embracing Christ. Regeneration (the new birth) logically and causally precedes faith, which is the instrumental cause of justification, or being declared righteous in God's sight.
The scriptures to confirm this doctrine are legion: some additional passages which teach that God sovereignly creates in his elect a new, “born again” heart which believes in him, and that he alone gives the faith and repentance of those who believe are Deut. 30:6; Jer. 31:33; 32:40; Ezek. 11:19-20; 37:3-6, 11-14; Mat. 16:15-17; Luk. 10:21; John 3:27; 5:21; 6:37-40, 45; Acts 5:31; 11:18; 16:14; 18:27; 1 Cor. 4:7; 2 Cor. 4:6; Eph. 2:1-10; Phil. 1:29; 2 Tim. 2:25-26; Jam. 1:18; 1 Pet. 1:3; 2 Pet. 1:1; 1 John 2:29). But one of the simplest, clearest passages that teaches this truth is 1 John 5:1. There, the apostle does not say that “everyone who is born again has believed,” but rather quite the opposite: “Everyone who believes that Jesus is the Christ has been born of God”. In other words, if you believe in Christ, it is because you have been born again.