Luther added the word "alone" (allein in German) to Romans 3:28 controversially so that it read: "So now we hold, that man is justified without the help of the works of the law, alone through faith"[8] The word "alone" does not appear in the Greek texts,[9] but Luther defended his translation by maintaining that the adverb "alone" was required both by idiomatic German and the apostle Paul's intended meaning,[10] and that sola was used in theological tradition before him.
Apologist James Swan lists numerous Catholic sources that also translated Romans 3:28 with the word "alone," or testified to others doing so before Luther.[11]