Note:
Luther says that relying on external acts to gain forgiveness of sins is a false confidence. He isn’t saying that good works are bad or should be avoided. It’s the misplaced confidence and the belittling of Christ’s work that makes our works something to be disdained. Absent that attitude, the good works and penance would be welcomed.

Here at the climax of Holy Week especially, we dare not belittle Christ’s work on our behalves.

Quote:
“Beware, lest you do as those perverse people who torture their hearts with their sins and strive to do the impossible, namely, 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. Unfortunately such false confidence in penance and pilgrimages is widespread.”  (page 12)

Source: Luther, Martin. “A Meditation on Christ’s Passion” (1519) Luther’s Works Vol. 42. Philadelphia: Fortress Press, 1969.