Jerome, Commentary on Galatians, [J.P. Migne, Editor]. Patrologiae Tomus XXVI. Paris: D’Ambroise, Pres La Barriere D’Enfer, ou Petit-Montrouge, 1845. pp. 307-438.
Jerome, speaking of Galatians 4:7, pulls the reader from the Latin back to Greek. Where the Latin says, “not to obey the truth” the Greek says something much more like “not to believe the truth” (Jerome, Galatians, 401). He goes on to explain that if we believe that Jesus both gave and did grace and truth, it is our obligation to believe him and act upon that belief. To do otherwise and to think that came from God is foolish.
Jerome notes a scribal error in Latin manuscripts. some of which say, “...is not from God who called…” but which should read, “...is not from him who called…” (Jerome, Galatians, 402). He does recognize that the “him” in the sentence is God nonetheless. It is certainly the work of God to call and of a man “either to believe, or not to believe” (Jerome, Galatians, 402, personal translation).
Verse nine makes a comparison to leavening, which works through the whole loaf. Jerome quickly points out that language about infusing or working through the lump is more faithful to the Greek than is language about “corruption” used in some translations (Jerome, Galatians, 402). In some contexts corruption is the right idea, but Jerome does not think it fits here. Though the metaphor in both cases is the same, that the leavening spreads through the whole mass, here it may be that Paul is speaking to the spread of good doctrine. Here, in verse nine, Paul continues to say he trusts in the Galatians that they are in the Lord. They should expect good doctrine to grow (Jerome, Galatians, 403).
Counter to the Galatians, in verse 10, Paul says the one who troubles them is bringing on his own judgment. Jerome recognizes that Paul is not acting as the judge, but he is entrusting that judgment to God (Jerome, Galatians, 403). Jerome compares this burden of judgment to the burdens which the Pharisees would bind on others. They are burdens which no human can carry. Only Jesus, who overcame the world, can do so (Jerome, Galatians, 404).