“The forgiveness of guilt, the heavenly indulgence, is granted to no one on account of the worthiness of his contrition over his sins, nor on account of his works of satisfaction, but only on account of his faith in the promise of God, ‘Whatever you loose . . . shall be loosed,’ etc. Although contrition and good works are not to be neglected, one is nevertheless in no case to build upon them, but only upon the sure words of Christ, who pledges to you that when the priest looses you, you shall be loosed. Your contrition and works may deceive you, and the devil will very soon overturn them in [the hour of] death and of temptation [anfechtung]. But Christ, your God, will not lie to you, nor will he waver; neither will the devil overturn his words for him. If you build upon them with a firm faith, you will be standing on the rock against which the gates and all the power of hell cannot prevail [Matt. 16:18]” (LW 35:12).