Quoting from the Source

I was intrigued this week to discover, with a little research, that St. Martin's response to the devil "The Lord is my helper, I shall not fear, what can man do to me?  is straight out of the Bible from the letter to the Hebrews (Hebrews 13.6) Κύριος ἐμοὶ βοηθός, [καὶ] οὐ φοβηθήσομαι: τί ποιήσει μοι ἄνθρωπος; and the exact same phrase is also used in Psalm 118.  I wonder whether quoting biblical passages is as commonplace in hagiographers such as Supulcius as I would expect it to be and whether at this point in the late 4th early 5th century these passages and letters would have been widely available to the public.  Obviously, in this particular incident, perhaps Martin, in addition to drawing strength from the words themselves, also gains an aspect of authority from where the words come from and who used them before (as it has been suggested that Paul wrote Hebrews).