John Wesley on Galatians 2:15

We - St. Paul, to spare St. Peter, drops the first person singular, and speaks in the plural number. Gal 2:18, he speaks in the first person singular again by a figure; and without a figure, Gal 2:19, &c. Who are Jews by nature - By birth, not proselytes only. And not sinners of the gentiles - That is, not sinful Gentiles; not such gross, enormous, abandoned sinners, as the heathens generally were.