Acts 19:1

Ephesus was a city of great note in Asia, famous for a temple built there to Diana, which was one of the wonders of the world: thither Paul came to preach the gospel while Apollos was at Corinth (Act 19:1); while he was watering there, Paul was planting here, and grudged not that Apollos entered into his labours and was building upon his foundation, but rejoiced in it, and went on in the new work that was cut out for him at Ephesus with the more cheerfulness and satisfaction, because he knew that such an able minister of the New Testament as Apollos was now at Corinth, carrying on the good work there. Though there were those that made him the head of a party against Paul (Co1 1:12), yet Paul had no jealousy of him, nor any way disliked the affection the people had for him. Paul having gone through the country of Galatia and Phrygia, having passed through the upper coasts, Pontus and Bithynia, that lay north, at length came to Ephesus, where he had left Aquila and Priscilla, and there found them. At his first coming, he met with some disciples there, who professed faith in Christ as the true Messiah, but were as yet in the first and lowest form in the school of Christ, under his usher John the Baptist.

— Matthew Henry's Concise Commentary (public domain)