The Devil Hates Forgiveness of Sin

The article of the forgiveness of sins is the most important, and it is of all the most comforting. To Satan it is truly the worst, and it is the most hateful. This is the reason why Paul always has on his tongue: grace, grace, grace! He does this to spite the devil.

Source: Quoted in Ewald M. Plass, What Luther Says, A Practical In-home Theology for the Active Christian. St. Louis: Concordia Publishing House. 1959 Edition, 10th Printing (1994), p. 515.