John Calvin on Acts 18:22-23

22. When he came down to Caesarea. Though Luke saith in a word that Paul saluted the Church at Jerusalem, yet is it certain that he was drawn thither with some great necessity. And yet we may gather by this text that he stayed not long at Jerusalem, peradventure because things fell not out as he would. Moreover, he declareth that his journey in his return was not idle or barren, in that he saith that he strengthened all the disciples, undoubtedly not without great pains-taking, because he was enforced to go hither and thither, and oft to turn out of his way; for this word [καθεξης] doth signify a continual course. Now, we have already declared (Acts 9:36) in what respect those be called disciples who had given their names to Christ, and professed the name of Christ; to wit, because there is no godliness without true instruction. They had, indeed, their pastors under whom they might profit. Yet the greater Paul’s authority was, and the more excellent spirit he had given him, so they were not a little strengthened by his by them, especially seeing he was the chief work-master in the founding of all these churches.

Acts 18:24-28

24. And a certain Jew named Apollos, born in Alexandria, an eloquent man, came to Ephesus, being mighty in the Scriptures. 25. He was instructed in the way of the Lord, and being fervent in the spirit, he spake and taught diligently those things which are the Lord’s, knowing only the baptism of John. 26. And he began to speak freely in the synagogue: whom when Priscilla and Aguila had heard, they took him to their company, and showed him the way of the Lord more perfectly. 27. And when he was determined to go into Achaia, the brethren exhorting him, wrote to the disciples that they should receive him: who, when he was come, he helped them much who had believed through grace. 28. For he overcame the Jews mightily, and that openly, showing by the Scriptures that Jesus was Christ.