3. Him would Paul have to go forth with him--This is in harmony with all we read in the Acts and Epistles of Paul's affectionate and confiding disposition. He had no relative ties which were of service to him in his work; his companions were few and changing; and though Silas would supply the place of Barnabas, it was no weakness to yearn for the society of one who might become, what Mark once appeared to be, a son in the Gospel [HOWSON]. And such he indeed proved to be, the most attached and serviceable of his associates (Php 2:19-23; 1Co 4:17; 16:10, 11; 1Th 3:1-6). His double connection, with the Jews by the mother's side and the Gentiles by the father's, would strike the apostle as a peculiar qualification for his own sphere of labor. "So far as appears, Timothy is the first Gentile who after his conversion comes before us as a regular missionary; for what is said of Titus (Ga 2:3) refers to a later period" [WIES]. But before his departure, Paul
      took and circumcised him--a rite which every Israelite might perform.
      because of the Jews . . . for they knew all that his father was a Greek--This seems to imply that the father was no proselyte. Against the wishes of a Gentile father no Jewish mother was, as the Jews themselves say, permitted to circumcise her son. We thus see why all the religion of Timothy is traced to the female side of the family (2Ti 1:5). "Had Timothy not been circumcised, a storm would have gathered round the apostle in his farther progress. His fixed line of procedure was to act on the cities through the synagogues; and to preach the Gospel to the Jew first and then to the Gentile. But such a course would have been impossible had not Timothy been circumcised. He must necessarily have been repelled by that people who endeavored once to murder Paul because they imagined he had taken a Greek into the temple (Ac 21:29). The very intercourse of social life would have been almost impossible, for it was still "an abomination" for the circumcised to eat with the uncircumcised" [HOWSON]. In refusing to compel Titus afterwards to be circumcised (Ga 2:3) at the bidding of Judaizing Christians, as necessary to salvation, he only vindicated "the truth of the Gospel" (Ga 2:5); in circumcising Timothy, "to the Jews he became as a Jew that he might gain the Jews." Probably Timothy's ordination took place now (1Ti 4:14; 2Ti 1:6); and it was a service, apparently, of much solemnity--"before many witnesses" (1Ti 6:12).

JFB.