How do we know Christ's sacrifice was enough for our sins?

When Jesus declared 'It is finished' just prior to His death, He affirmed the completion of the redemptive work necessary for our salvation. This statement signifies that every requirement of the law has been met and that He bore the penalty for our sins on the cross. The fullness of His sacrifice ensures that no further actions on our part are necessary for our salvation. Romans 5:6-8 further affirms that Christ died for the ungodly, confirming that it is through faith in His finished work that we receive reconciliation with God.