John Chrysostom : [Paul] left them in Ephesus so that they might teach. Indeed those who had stayed with him for such a long time had learned many things; he had not, however, completely detached them from the Jewish customs. — CATENA ON THE ACTS OF THE APOSTLES 18.19 John Chrysostom : "And with him Priscilla" - lo, a woman also - "and Aquila." But these he left at Ephesus. With good reason, namely, that they should teach. For having been with him so long time, they were learning many things: and yet he did not at present withdraw them from their custom as Jews. "And he came to Ephesus, and left them there: but he himself entered into the synagogue, and reasoned with the Jews." — Homily on Acts 40 John Chrysostom : "And they came to Ephesus, and there he left them": for he did not wish to take them about with him, but left them at Ephesus. But they subsequently dwelt at Corinth, and he bears high testimony to them, and writing to the Romans, salutes them. ... It was not for nothing that he left them at Ephesus, but for Apollos' sake, the Spirit so ordered it, that he might come with greater force to the attack upon Corinth. — Homily on Acts 40 Oecumenius : He left Priscilla and Aquila in Ephesus, he said, [and did this with good reason], as if they were teaching there. For since they had been associated with him for so long, they had learned very many things; yet he had not been able to dissuade them from the Jewish custom. For this reason, when Paul was a prophet, and knew that he would return, he did not simply promise that he would return, but added, if God wills. Clearly teaching us not to promise anything about the future except by adding, if God wills. For no one knows what a coming day will bring forth. [CHRYSOSTOM] — Commentary on Acts