Ambrosiaster on the Righteousness of God
Ambrosiaster was an anonymous Christian writer from the late 4th century. The name was given to him by Erasmus in the 16th century because his commentary on Paul’s epistles was mistakenly attributed to Saint Ambrose of Milan. Most likely, however, Ambrosiaster was a Roman convert, who was deeply engaged in theological debates in Rome, and had a very strange dislike of Greek exegesis. He really is a Vulgate-only kind of a guy.
Anyway, his Romans commentary is quite remarkable, one of the best first commentaries on Romans. He was very focused on the literal sense of Scripture and believed that justification by faith was very important. In many ways, Ambrosiaster was a proto-Protestant and had a big influence on the later Augustine.
Ambrosiaster says some amazing stuff on Rom. 1.17:
Paul says this because the righteousness of God is revealed in the person who believes whether Jew or Greek. He calls it the righteousness of God because God freely justifies the ungodly by faith, without the works of the law, just as he says elsewhere: That I may be found in him, not having a righteousness of my own, based on law, but that which is through faith in Christ, the righteousness from God that depends on faith [Phil. 3.9]. He says that this same righteousness is revealed in the gospel, when God grants faith to man, through which he may be justified ... Through faith for faith. What does this mean, except that the faith of God is in him because he promised, and the faith of man is in him because he believes the one who promises, so that through the faith of the God who promises, the righteousness of God might be revealed in the faith of the man who believes? To the believer, God appears to be just, but to the unbeliever, he appears to be unjust. Anyone who does not believe that God has given what he promised denies that God is truthful. This is said against the Jews, who deny that Christ is the one whom God has promised.
A few interesting observations:
(a) Ambrosiaster focuses on the faith (not the righteousness) that God grants to man.
(b) Ambrosiaster connects the righteousness of God with the truth of God.
(c) Ambrosiaster sees a connection between God’s faithfulness and human faith, i.e., from faith to faith.
(d) There is also a promise-fulfilment motif that emerges, even more so in his comments on Rom. 3.21-26: "Therefore, the righteousness of God appears to be mercy, because it has its origin in the promise, and when God's promise is fulfilled, it is called the righteousness of God. For it is righteousness when what is promised has been delivered".
(e) Note also, in Rom. 3.22, Ambrosiaster is definitely an objective genitive proponent (“faith in Christ” not “faithfulness of Christ”). He also has no problem with human faith being the instrument that reveals God's righteousness.


Hi Michael - what is the best modern translation of Ambrosiaster. I am a NT Prof getting reading to lead a seminar class on Romans - thanks
Romans 3:21 brings Paul's argument back to 1:17, and means: “But now, the from-God, apart-from-law righteousness has been manifested, something which was testified both in the Torah in Genesis 15:6, and in the prophets in Habakkuk 2:4.”