甚麼是善工（好行為）？
善工是上帝藉著我，在我裏面所作的工。如果上帝作了這工，那麼這就是上帝的工。
我們教導說：與上帝和好，成就公義，去除罪孽是一件高尚的、偉大的、榮耀的工，必須唯獨基督，上帝的兒子，才能成就。善工是獨一真神，出於他的恩典，唯獨他作的正確的、純淨的工。與上帝的工相比，我們的工不能作甚麼，所以，人的工也就毫無價值，歸於無有了。
因為是善工，所以是上帝藉著我，在我裏面所作的工。如果上帝作了這工，那麼這就是上帝的工，那麼整個世界又怎麼可以與上帝和他的工相比呢？善工絕不是這世界上的財物可以償付，或與之相比的。
我不能藉著某項善工成為義人，因為基督的血和恩典已經成就這點，並不靠我的善工。
為了讚美榮耀上帝，為了幫助鄰舍，為了鄰舍的好處，善工還是被行了出來。——馬丁路德（AE 59:270–271）（寫給Justus Menius的前言，從聖經裏反對重洗派的教義和秘密，1530）
We teach that reconciling God, making righteous, and wiping away sin is such a lofty, great, glorious work that Christ, God’s Son, alone must do it, and that it is properly, purely, simply, and uniquely a work of the one true God and of His grace, in relation to which our work is and can do nothing.
For if it is a good work, then God has done it through and in me. If God has done it and it is God’s work, what is the whole world in comparison with God and His work?
Even though I do not become righteous through such a work (for this must already have happened through Christ’s blood and grace, without works),
it has still been done to the praise and honor of God, for the help and well-being of my neighbor. None of these things can be paid for or compared with the world’s goods.(Preface to Justus Menius, The Doctrine and Secret of the Anabaptists, Refuted from Scripture, 1530)(AE 59:270–271)
