How do we know that God's grace is essential for salvation?

The necessity of God's grace for salvation is rooted in the doctrine of total depravity, which posits that all humans are born with a sinful nature that leads to sinfulness without divine intervention. The assertion that 'by the grace of God, I am what I am' (1 Corinthians 15:10) illustrates that any goodness or righteousness in a believer's life is solely a product of God’s grace working within them. In Reformed theology, grace is not just a benevolent offer, but an essential element enabling a person to respond to God and experience true conversion, further affirming that salvation is entirely a work of God.