How do we know that salvation is a work of the Spirit?

Salvation is recognized as a spiritual work of God, not of human effort. This is clearly seen in the comparison of being born again, as explained in John 3:14-16. Jesus draws an analogy with Moses lifting the serpent, illustrating that just as those who looked upon the serpent were healed, those who look to Christ in faith are granted eternal life. New birth through the Spirit manifests life and righteousness, confirming that true salvation can only come from God’s action within us, rather than through our attempts to obey the law.