And it came to pass, that, while Apollos was at Corinth, Paul having passed through the upper coasts came to Ephesus: and finding certain disciples,
Paul Arrives at Ephesus, and Meets with Certain Disciples of the Baptist, who, upon Receiving from him Fuller Light, are Baptized, Receive the Holy Spirit, and Speak with Tongues (19:1-7)
And it came to pass, that, while Apollos was at Corinth - where his ministry was so powerful that a formidable party in the church of that city gloried afterward in his type of preaching in preference to Paul's (1 Corinthians 1:12; 1 Corinthians 3:4), no doubt from the marked infusion of Greek philosophic culture which distinguished it, and which seemed to be the very thing which the apostle studiously avoided (1 Corinthians 2:1-5):
Paul having passed through the upper coasts (or 'parts') - meaning the interior parts of Asia Minor, traveling westwards toward Ephesus; with reference to which (as lying on the seacoast) all from Galatia and Phrygia was elevated, and partly mountainous.
Came to Ephesus (see the note at Acts 18:19) - thus making good his conditional promise (Acts 18:21): "and finding certain disciples,"