acts 18:27 And when he was disposed to pass into Achaia, the brethren wrote, exhorting the disciples to receive him: who, when he was come, helped them much which had believed through grace: - Free Bible Online

      27, 28. And when he was disposed--"minded," "resolved."
      to pass into Achaia--of which Corinth, on the opposite coast (see on Ac 18:1), was the capital; there to proclaim that Gospel which he now more fully comprehended.
      the brethren--We had not before heard of such gathered at Ephesus. But the desire of the Jews to whom Paul preached to retain him among them for some time (Ac 18:20), and his promise to return to them (Ac 18:21), seem to indicate some drawing towards the Gospel, which, no doubt, the zealous private labors of Priscilla and Aquila would ripen into discipleship.
      wrote, exhorting the disciples to receive him--a beautiful specimen of "letters of recommendation" (as Ac 15:23, 25-27, and see 2Co 3:1); by which, as well as by interchange of deputations, &c., the early churches maintained active Christian fellowship with each other.
      when he was come, helped them much--was a great acquisition to the Achaian brethren.
      which believed through grace--one of those incidental expressions which show that faith's being a production of God's grace in the heart was so current and recognized a truth that it was taken for granted, as a necessary consequence of the general system of grace, rather than expressly insisted on. (It is against the natural order of the words to read them, as BENGEL, MEYER, and others, do, "helped through grace those who believed").

JFB.