And when they were come to him, he said unto them, Ye know, from the first day that I came into Asia, after what manner I have been with you at all seasons,
Note 1 at Ac 20:18: Paul had originally come into Asia Minor, or what the New Testament calls Asia (see note 3 at Ac 16:6), during the first part of his second missionary trip (see note 1 at Ac 18:22). However, he was forbidden by the Holy Ghost to preach the Word in Asia at that time (Ac 16:6) and was instead directed to Philippi in Europe (Ac 16:9-12). About two years later, during this same second missionary trip, Paul ministered briefly in the synagogue in Ephesus (Ac 18:19-21).
In this instance, where Paul was addressing the leaders of the church at Ephesus, he was probably referring to his third missionary trip when he spent three years in ministry at Ephesus (Ac 20:31). This was Paul's longest recorded stay in any one place.