How do we know God redeems sinners?

The doctrine of God's pleasure in redeeming sinners is rooted in Isaiah 53:10, which states, 'Yet it pleased the Lord to bruise Him; He hath put Him to grief.' This indicates that God's sovereign will is intricately involved in the act of redemption. Jesus' sacrifice was not a response to an obligation but stemmed from God's good pleasure. It underscores His perfect justice and mercy as He is both just and the justifier of those who believe (Romans 3:26). Through this, we see God's ultimate delight in the redemption of His elect, fulfilling His purpose.