Matthew Henry Commentary Acts 18:18-23

"And Paul, having tarried after this yet many days, took his leave of the brethren, and sailed thence for Syria, and with him Priscilla and Aquila: having shorn his head in Cenchreae; for he had a vow. And they came to Ephesus, and he left them there: but he himself entered into the synagogue, and reasoned with the Jews. And when they asked him to abide a longer time, he consented not; but taking his leave of them, and saying, I will return again unto you if God will, he set sail from Ephesus. And when he had landed at Caesarea, he went up and saluted the church, and went down to Antioch. And having spent some time [there], he departed, and went through the region of Galatia, and Phrygia, in order, establishing all the disciples." — Acts 18:18-23 (ASV)

While Paul found he did not labor in vain, he continued laboring. Our times are in God's hand; we purpose, but He disposes. Therefore, we must make all promises with submission to the will of God—not only if providence permits, but also if God does not otherwise direct our actions.

It is a very good refreshment for a faithful minister to have for a while the fellowship of his brothers. Disciples are encompassed by weakness; ministers must do what they can to strengthen them by directing them to Christ, who is their Strength. Let us earnestly seek, in our respective places, to promote the cause of Christ, forming plans that appear to us most proper, but relying on the Lord to bring them to pass if He sees fit.