Therefore read these words “me” and “for me” with great emphasis, and accustom yourself to accepting this “me” with a sure faith and applying it to yourself. Do not doubt that you belong to the number of those who speak this “me.” Christ did not love only Peter and Paul and give Himself for them, but the same grace belongs and comes to us as to them; therefore we are included in this “me.” For just as We cannot deny that we are all sinners, and just as we are obliged to say that through his sin Adam destroyed us and made us enemies of God who are liable to God’s wrath and judgment and worthy of eternal death—for all terrified hearts feel and confess this, in fact, more than is proper—so we cannot deny that Christ died for our sins in order that we might be justified. For He did not die to make the righteous righteous; He died to make sinners into righteous men, the friends and sons of God, and heirs of all heavenly gifts. Therefore since I feel and confess that I am a sinner on account of the transgression of Adam, why should I not say that I am righteous on account of the righteousness of Christ, especially when I hear that He loved me and gave Himself for me? Paul believed this most firmly, and therefore he speaks with such πληροφορία [full of assurance].
Martin Luther, Lectures on Galatians (1535) on Galatians 2:21, Luther’s Works 26.179