Nowhere in all known Greek writings is the precise phrase ἐκ πίστεως ("out of" or "from faith") found until the Greek version of Habakkuk 2:4, and some of the scribes transmitting that text altered it. It is this phrasing that Paul adopts in the crucial lines of Roman 1:16-17, and rewords elsewhere. What, then, was the intended sense of this unique wording? Dr. Roy E. Ciampa recently retired as S. Louis and Ann W. Armstrong Professor of Religion and chair of the Department of Biblical and Religious studies at Samford University in Birmingham, Alabama. He is currently teaching at Gordon Conwell Theological Seminary, where he was previously on faculty. His publications include The Presence and Function of Scripture in Galatians 1 and 2 (WUNT 2/102) and (with Brian Rosner) The First Letter to the Corinthians (PNTC). For more detail on the topic of this episode, see Roy E. Ciampa, "Habakkuk 2:4 in Romans: Echoes, Allusions, and Rewriting," pp. 11-29 of Scripture, Texts, and Tracings in Romans. 

Check out related programs at Wheaton College:

B.A. in Classical Languages (Greek, Latin, Hebrew): https://bit.ly/40QfwEB 

M.A. in Biblical Exegesis: https://bit.ly/4fLnZxd