Because he was of the same craft. — The calling was one which St. Paul had probably learnt and practised in his native city, which was noted then, as now, for the rough goat’s-hair fabrics known to the Romans, from the name of the province, as Cilicium (= sack-cloth). The material was one used for the sails of ships and for tents, and on the whole, though some have supposed that leather was used for the latter, it seems more probable that this was the material which St. Paul worked at. It may be added that Pontus, from which Aquila came, was also famous for the same manufacture, the material in each case being furnished by the goats which fed upon the slopes of the Taurus, and the mountain ranges of that province. The fact that St. Paul had learnt this trade is not inconsistent with the comparative opulence suggested by his education both in boyhood at Tarsus and at the feet of Gamaliel in Jerusalem. The Rabbinic proverb, that “He who does not teach his son a trade, teaches him to be a thief,” made such instruction almost universal. So the great Hillel was a carpenter. Here, it is clear, he took the course of working for his livelihood, as he had done at Thessalonica, that he might keep himself from the suspicion of self-interest in his work as a teacher (1 Corinthians 9:15-19; 2 Corinthians 11:7-13). Such was the beginning of his labours at Corinth. A new artisan was working for wages, or as a partner, probably the latter, as afterwards with Philemon (Philemon 1:17), in the workshop of the Jew, not as yet known to the outer world as more than a Jew, who had recently arrived in Corinth from Rome.
(3) We may add to this motive the principle on which St. Paul acted of being “all things to all men,” and, therefore, as a Jew to Jews (1 Corinthians 9:20). A Nazarite vow would testify to all his brethren by blood that he did not despise the Law himself nor teach other Jews to despise it. (See Notes on Acts 21:21-24.) Such a vow, involving, as it did, for a time a greater asceticism than that of common life, furnishes a link in the succession of thoughts in 1 Corinthians 9:22-25, between the Apostle’s being made “all things to all men” and his “keeping under his body, and bringing it into subjection.”