Protestants in the sixteenth century were fond of quoting a number of passages from patristic sources in which the “exclusive particle” (i.e., “alone”) was used in connection with justification.
Philip Melanchthon, for example, does this in his Responsiones ad impios articulos Bavaricae inquisitionis (“Answers to the Impious Articles of the Bavarian Inquisition”) in Article 23, “Whether man is justified by faith alone?” While acknowledging that ancient writers sometimes “spoke rather negligently” on this topic, and that his predecessors in the faith “spoke sometimes more, sometimes less clearly,” he nevertheless believes that they “bear witness to the true opinion.” As illustration, he quotes a passage from one of Bernard of Clairvaux’s sermons on the Song of Songs and a passage from Basil of Caesarea, Homily 20, on humility.
Therefore no truly prudent man will think himself great because of his own wisdom, or because of the other things I have spoken of, but will attend rather to the excellent counsel of the blessed Anna, and the prophet Jeremias: Let not the wise man glory in his wisdom, and let not the strong man glory in his strength, and let not the rich man glory in his riches(Jer. ix. 23). But in what shall man glory: and in what is man great? Let him that glorieth glory in this, he said, that he understandeth and knoweth me, that I am the Lord. This is the grandeur of man, this his glory and greatness, truly to know Him Who is great, to cling to Him, and to seek for the glory of the Lord of glory. For the Apostle says to us: He that glorieth, may glory in the Lord (I Cor. 1. 31) where he declares: But of him are you in Christ Jesus, who of God is made unto us wisdom, and justice, and sanctification, and redemption: That, as it was written: He that glorieth, may glory in the Lord.
This is complete and perfect glorying in God, when a man is uplifted, not because of his own justice (μήτε ἐπὶ δικαιοσύνῃ…τῇ ἑαυτοῦ), but because he knows he is empty of true glory, and made just only through his faith in Christ 2 (…πίστει δὲ μόνῃ τῇ εἰς Χριστὸν δεδικαοιωμένον). In this Paul gloried, that he thought nothing of his own justice; that he sought that justice which comes through Christ, which is from God, justice in faith (Phil. iii. 9); and that he might know Him, and the power of His resurrection, and the sharing of His sufferings, and be made like Him in His death, if by any means he might himself attain to the resurrection which is from the dead. It is here that the whole top-loftiness of arrogance falls down. Nothing is left to you to glory in, O man; whose true glorying and whose hope is in mortifying yourself in all things, and in seeking for that future life in Christ, of which we have already a foretaste when we live wholly in the love and in the grace of God.
And it is God who worketh in you both to will and to accomplish, according to his good will (Phil. ii. 13). And God has made known to us His own wisdom, through His Spirit, for our glory (I Cor. ii. 7, 10). And in all our efforts it is God who gives us strength. I have laboured more abundantly than all they, says Paul, yet not I, but the grace of God with me (I Cor. xv. 10). And God has delivered us from danger, and beyond all human expectation. But we, he says, had in ourselves the answer of death, that we should not trust in ourselves, but in God, who raiseth the dead: who hath delivered and doth deliver us out of so great dangers: in whom we trust that he will yet also deliver us (II Cor. i. 9, 10).