For they have set out for his sake and have accepted nothing from the heathen.
ὑπὲρ γὰρ τοῦ ὀνόματος ἐξῆλθον μηδὲν λαμβάνοντες ἀπὸ τῶν ἐθνικῶν.
Haydock Catholic Bible Commentary: 3 John
Taking nothing of the Gentiles. These ministers and preachers of the gospel, whom S. John recommends, took care, as S. Paul did, not to take any thing of the Gentiles, to whom they preached, lest they should be thought to preach to get money by it. But he puts Gaius in mind, that by assisting such men, he would become a fellow labourer in the gospel, and have a share in their reward. Wi.