How do we know that Christ fulfills the law for us?

The assurance that Christ fulfills the law on our behalf is evidenced by His sinless life and sacrificial death. The law is designed to show us our guilt and our need for a Savior (Romans 3:20), and Christ embodies this fulfillment by living in perfect obedience to it. He did not merely come to guide us toward obedience; rather, He completely satisfied the demands of the law through His righteous life and substitutionary death. This redemptive work is what enables believers to be declared righteous before God. He took on the sin of His people and bore the wrath meant for them, thus satisfying divine justice and granting us forgiveness and reconciliation with God (2 Corinthians 5:21).