Acts 18:7

"And he departed thence, and entered into a certain man's house, named Justus, one that worshipped God, whose house joined hard to the synagogue." See how having again said, "Henceforth"--for all that, he does not neglect them; so that it was to rouse them that he said this, and thereupon came to Justus, whose house was contiguous to the synagogue, so that even from this they might have jealousy, from the very proximity. "And having removed thence he came into the house of one named Justus, that worshipped God, whose house was contiguous to the synagogue," and there abode, by this wishing to persuade them that he was in earnest to go to the Gentiles. Accordingly, mark immediately the ruler of the synagogue converted, and many others, when he had done this.

And departing from there, he entered the house of a certain man named Titus Justus. The name Justus is also written in Greek, because either this name was proper to the man, or he was surnamed this way by the Romans who knew him due to his merit of justice. However, it should not be thought that this is Titus, the disciple of the Apostle Paul, to whom he himself wrote an Epistle and appointed him bishop of the Cretans. For that Titus was with him much earlier, when he came from Antioch to Jerusalem concerning the question of circumcision, with Barnabas still accompanying him. For the same Paul says to the Galatians: Then after fourteen years I went up again to Jerusalem with Barnabas, and took Titus with me, and I communicated with them concerning the Gospel which I preach among the Gentiles. For he communicated with them about the Gospel he was preaching, diligently inquiring in the council of the apostles whether he was correct in preaching that the Gentiles could attain salvation through the baptism of faith without circumcision; not that he himself had any doubt about this matter, but that the minds of those who were doubting might be confirmed by the authority of the apostolic council.