Why is Christ's finished work on the cross important?

The importance of Christ's finished work lies in its completeness and sufficiency for our salvation. In John 17:4, Jesus proclaims, 'I have finished the work which You gave Me to do.' This signifies that through His life, death, and resurrection, every necessary act for our redemption has been accomplished. It assures believers that there is nothing more to be done to gain favor with God; He has done it all. This promise of substitution and sacrifice provides immense comfort, as we are declared righteous and equipped to approach God confidently, as seen in Romans 5:1, where it states that we have peace with God through Jesus Christ.