How do we know that salvation comes through God's power?

In 1 Corinthians 2:4-5, Paul emphasizes that his preaching was not reliant on persuasive words but rather a demonstration of the Spirit's power. This reinforces the sovereignty of God in salvation; it is a miraculous work that cannot be accomplished by human effort or decision. Ephesians 2:8-9 further asserts that faith itself is a gift from God, ensuring that no one can boast in their own deeds. Salvation is purely an act of God’s grace, showcasing His power to resurrect spiritually dead sinners to new life.