How do we know grace is unearned in Christianity?

Grace is fundamentally understood as unmerited favor that stems from God's love and mercy. Ephesians 2:8-9 emphasizes that we are saved by grace through faith, and this is not of ourselves; it is the gift of God. This means that we do not earn our salvation or God's favor through works or personal merit, but it is given simply because of God's love and choice before the foundation of the world. This doctrine helps believers understand their dependence on God for salvation and sanctification.