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.
In Galatians 1:18 Paul says he went to Jerusalem to see Peter. Jerome thinks it obvious that Paul would not have gone so as to see what he looked like, but to learn from and about this apostle (Jerome, Galatians, 329). This was an action intended to give honor to an existing apostle. The visit of fifteen days is taken by Jerome to bear symbolic importance. He lists several places in Judaism and Christianity where the number 15 is of prophetic significance. However, Jerome does not identify a particular meaning except to affirm his identity as an apostle (Jerome, Galatians, 330).
Jerome discusses Paul’s interactions from Galatians 1:19 in some detail. He didn’t see any of the apostles except Peter and James. Jerome notes that when he was in Jerusalem himself he was so occupied with the research work he did that he visited very few people. Paul was intent on his purpose, which was apparently not to build a relationship with all the apostles (Jerome, Galatians, 330). Rather, he was learning from Peter, as well as probably speaking to James “the brother of the Lord.” Jerome suggests this is where he obtained the various details not found elsewhere in Scripture, such as his account of post-resurrection appearances of Christ, found in 1 Corinthians 15 (Jerome, Galatians, 330).
Jerome further builds a case for people other than the original 12 apostles to be called apostles. In Galatians 1:19 he refers to James as an apostle, but it is the brother of Jesus, ot the brother of John. He also counts Silas and Jude as apostles (Jerome, Galatians, 331). Later, Stephen is counted as an apostle, as is James the Just of Jerusalem.
Galatians 1:20 seems almost like an interruption in the overall message. Jerome observes that Paul’s assertion of his truthfulness is artless enough, as is his account of meeting people, that it could not be falsehood. It lacks all the creativity someone would use to mislead anyone (Jerome, Galatians, 331).
Galatians 1:21-24 concludes Paul’s account of his trip to Jerusalem, describing his departure to Syria and Cilicia. For this reason the Christians around Judea didn’t know Paul, though they had heard about his conversion (Jerome, Galatians, 331). Jerome also points out that Paul would later use the brief nature of the isit to assert that he was, like the other apostles, trained by Jesus himself (Jerome, Galatians, 332).