From today's writing portion of Pray Now app (Treasury of Daily Prayer):
After man has thus become aware of his sin and is terrified in his heart, he must watch that sin does not remain in his conscience, for this would lead to sheer despair. Just as [our knowledge of] sin flowed from Christ and was acknowledged by us, so we must pour this sin back on him and free our conscience of it. Therefore beware, lest you do as those perverse people who torture their hearts with their sins and strive to do the impossible, mainly, get rid of their sins by running from one good work or penance to another, or by working their way out of this by means of indulgences. . . .
You cast your sins from yourself and onto Christ when you firmly believe that his wounds and sufferings are your sins, to be borne and paid for by him, as we read in Isaiah 53:6, "The Lord has laid on him the iniquity of us all." St. Peter says, "in his body has he borne our sins on the wood of the cross" [1 Peter 2:24]. St. Paul says, "God has made him a sinner for us, so that through him we would be made just" [2 Cor. 5:21]. You must stake everything on these and similar verses. The more your conscience torments you, the more tenaciously must you cling to them. If you do not do that, but presume to still your conscience with your contrition and penance, you will never obtain peace of mind, but will have to despair in the end. If we allow sin to remain in our conscience and try to deal with it there, or if we look at sin in our heart, it will be much too strong for us and will live forever. But if we behold it resting on Christ and [see it] overcome by his resurrection, and then boldly believe this, even it is dead and nullified. Sin cannot remain on Christ, since it is swallowed up by his resurrection. Now you see no wounds, no pain in him, and no sign of sin. Thus St. Paul declares that "Christ died for our sin and rose for our justification" [Rom. 4:25]
-- Martin Luther