How do we know that salvation does not depend on human decision?

Scripture makes it abundantly clear that salvation relies on God's sovereign will, not human decision. In John 1:13, it is said that we are born not of blood, nor of the will of the flesh, nor of the will of man, but of God. Additionally, Romans 9:16 affirms that it is not of him who wills, nor of him who runs, but of God who shows mercy. This reinforces the conviction that faith and repentance are not products of human effort but are graciously granted by God, aligning perfectly with the Reformed understanding of grace and salvation.