Righteousness and Faith

Quoniam autem in lege nemo justificatur apud Deum, manifestum est, quia justus ex fide vivit. Lex autem non est ex fide, sed qui fecerit ea, vivet in illis.  Exemplum quo probatur justus ex fide vivere, et non ex operibus, de Abacuc tulit, quod ita Septuaginta interpretes ediderunt: Justus autem ex fide mea vivit Aquila et Theodotio: Justus autem ex fide ejus vivit, id est, Dei. Considerandum itaque quia non dixerit, homo aut vir ex fide vivit, ne occasionem tribueret ad virtutum opera contemnenda; sed, justus ex fide vivit: ut quicumque fidelis esset, et per fidem victurus, non aliter posset ad fidem venire, vel in ea vivere, nisi prius justus fuisset, et puritate vitae quasi quibusdam ad fidem gradibus ascendisset. Potest ergo fieri, ut sit aliquis justus, et tamen non vivat absque fide Christi. Si legenti scrupulus commovetur, Pauli verba suscipiat, in quibus de se ait: Secundum justitiam, quae in Lege est, sine reprehensione. Erat igitur Paulus tunc justus in Lege, sed necdum vivere poterat, quia non habebat in se Christum loquentem: Ego sum vita. In quem credens postea coepit et vivere. Faciamus et nos aliquid simile huic quod dicitur, justus ex fide vivit; et dicamus: castus ex fide vivit, sapiens ex fide vivit, fortis ex fide vivit, et a caeteris virtutum partibus vicinam sententiam proferamus adversum eos, qui in Christum non credentes, fortes et sapientes, temperantes se putant esse, vel justis: ut sciant nullum absque Christo vivere, sine quo omnis virtus in vitio est. Sanctus Hieronymus, Commentariorum in Epistolam ad Galatas, Liber II

That no one is justified before God by the Law is made clear because, 'The righteous man lives by faith.' The law is not from faith, but, 'The man who does these things will live by them.' 1 To prove that the righteous man lives by faith and not by works Paul has taken an example from the prophet Habakkuk, which the  translators of the Septuagint have given as, 'The righteous man lives by faith in me.' 2 The translators Aquila and Theodotion have it as, 'The righteous man lives by faith in Him,' that is, in God. It should be observed that he did not say that a man lives by faith, lest he give excuse for the condemnation of virtuous deeds, but rather he said that the righteous man lives by faith, that he who would be faithful and through faith victorious cannot come to faith or in it live unless first he be righteous and by the purity of life have climbed certain steps to faith. It is therefore possible that someone may be righteous and yet not live by faith in Christ. If this troubles the reader, let him ponder the words of Paul, when he spoke about himself saying: 'As for righteousness according to the Law, I was blameless.' 3 So then Paul was righteous in the Law, but he was not yet able to live because he did not have Christ in him saying 'I am the Life,' 4 in whom  later believing he began to live. Let us make some similar expressions to, 'The righteous man lives by faith.' And so we may say: 'The chaste man lives by faith,' 'The wise man lives by faith,' 'The courageous man lives by faith,' and for the rest of the virtues let us apply a similar principle against those who do not believe in Christ, who think themselves to be courageous, wise, temperate, or righteous, that they may know that without Christ no one lives and that without Him every virtue is as vice. Saint Jerome, Commentary on the Letter to the Galatians, Book 2  1 Gal 3. 11-12 2 Hab 2.4  3 Philip. 3.6  4 Jn 9.25