What is the meaning of Acts 20:17-21?

17 And from Miletus he sent to Ephesus, and called the elders of the church. 18 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, 19 Serving the Lord with all humility of mind, and with many tears, and temptations, which befell me by the lying in wait of the Jews: 20 And how I kept back nothing that was profitable unto you, but have shewed you, and have taught you publickly, and from house to house, 21 Testifying both to the Jews, and also to the Greeks, repentance toward God, and faith toward our Lord Jesus Christ. (Acts 20:17-21 KJV)

William Burkitt’s Commentary

The foregoing verses acquainted us with how very intent Apostle Paul was upon his journey to Jerusalem at the feast of Pentecost, hoping then and there to have a precious opportunity to preach Jesus Christ, and him crucified, to his countrymen the Jews: now, to avoid being hindered in his expedition, he determines to slip by Ephesus, without touching there; but he could not satisfy himself without seeing of and speaking to the ministers of Ephesus, whom for that purpose he sends for to meet him at Miletus, and there in a grave and pious discourse, which warmed their hearts, and melted them into tears, he takes his farewell of them. 

Here note, 1. That St. Paul speaks much in his own vindication, but nothing by way of ostentation. A minister, when he is leaving his people, may modestly enough say something in his own vindication; for there are enough, as soon as his back is turned, will say more than is true by way of accusation.

Note, 2. That when the apostle here speaks much that looks like self-condemnation, it is rather to propound himself as a mirror for gospel ministers, and a pattern for all pious pastors; that whenever they leave their people they may go off with a clear conscience, and be able to appeal to the consciences of their people as touching their carriage and conversation amongst them.

Note, 3. The several particular instances of his ministerial faithfulness:

1. He instances in his own humility; though he was lofty in his ministry, yet was he lowly in his mind; He served the Lord with all humility of mind. The better any man is, the lower thoughts he has of himself. Almighty God renders that man most honourable, that minister most serviceable, whom he finds most humble. In his affectionateness in preaching the gospel, he mingles tears with his exhortation, Serving the Lord with all humility of mind, and with many tears.

2. In his constancy in preaching and private inspection: publicly in the synagogues, and privately from house to house, like a good shepherd, labouring to understand the state of his whole flock, and of every lamb in it, that no soul might miscarry through his neglect, for which the great and good Shepherd died.

3. He acquaints them, not only with the manner, but also with the matter of his preaching; namely, Repentance towards God, and faith in our Lord Jesus Christ; which two graces comprehend the sum of a Christian’s duty. Ministers must join these two together in their preaching, and our hearers must not separate them in their practice. Those who repent without believing, or believe without repenting, do indeed do neither.