Keep watch over yourselves and the entire flock of which the Holy Spirit has made you overseers. Be shepherds of the church of God, which He purchased with His own blood.
28. Take heed, therefore. He doth now apply his speech unto them, and by many reasons showeth that they must watch diligently, and that he is not so careful but because necessity doth so require. The first reason is, because they be bound to the flock over which they be set. The second, because they were called unto this function not by mortal man, but by the Holy Ghost.
It should seem the ship Paul and his companions were embarked in for Jerusalem attended him on purpose, and staid or moved as he pleased; for when he came to Miletus, he went ashore, and tarried thee so long as to send for the elders of Ephesus to come to him thither; for if he had gone up to Ephesus, he could never have got away from them.
Commenting on Acts 20:17-35
Therefore watch,.... Meaning both over themselves, and the flock; to prevent, if possible, false teachers entering in, and to nip the buds of heresy and schism, as soon as they appear, and to preserve themselves, and the church, from being carried away with the error of the wicked.