How do we know that Christ's redemption is effective?

The effectiveness of Christ's redemption is central to Reformed theology, rooted in his atoning sacrifice. Jesus Christ came into the world to redeem His people from sin, as stated in Matthew 1:21. This is further supported by the doctrine of election and the union of believers with Christ, which is emphasized in Ephesians 1:4-5. His resurrection guarantees that redemption is complete, as He conquered death and sin, sealing the promise that those who believe in Him will not perish but have eternal life. Thus, the assurance of salvation lies not in our works but solely in the completed work of Christ, which is both perfect and complete.