Martin Luther once wrote to a young friend of his who was struggling with guilt and failure:
When the devil throws our sins to us and declares that we deserve death and hell, we ought to speak thus: “I admit that I deserve death and hell. What of it? Does this mean that I shall be sentenced to eternal damnation? By no means. For I know One who suffered and made satisfaction in my behalf. His names is Jesus Christ, the Son of God. Where He is, There I shall be also.”
Excerpt from Michael Reeves book: Rejoicing in Christ, pg. 63.