We must, therefore, sharply distinguish between the proclamation of faith and good works, nevertheless, good works are only like the foliage of a tree or the fruit-apples, pears, or the like-that a tree produces. Faith, indeed, is a tree that produces foliage and fruit. Good works are meant to remain here below, on earth, among people, serving our neighbor’s welfare. Faith on the other hand, ascends on high, deals directly with God, receives the forgiveness of sins, life, and salvation, which are offered in Christ through the gospel. That faith, as we have said before, is not some vain or empty illusion, but is rather a living confidence, so that a person relies on the gospel’s promise with all his heart, and courageously defies sin, death, and the devil: “But he that believeth not shall be damned.”
-Martin Luther. Complete Sermons of Martin Luther 6:139.