{9} For I know this, that after my departing shall grievous wolves enter in among you, not sparing the flock.

(9) A prophecy of pastors that would immediately degenerate into wolves, against those who boast and brag only of a succession of persons.

People's New Testament

20:29-31 Grievous wolves. The figure of the flock is still kept up. The grievous wolves were false teachers, and the special reference is to the Judaizing teachers, who taught that the Gentile Christians must keep the Jewish law. Paul's ministry was a long battle with the schismatics. See 1Ti 1:3,4,20; 2Ti 1:15 2:17 See also 3Jo 1:9,10. By turning to these references the names of some six of these grievous wolves will be found. Also in Revelation we learn that there were false teachers at Ephesus (Re 2:6).

Wesley's Notes

20:29 Grievous wolves - From without, namely, false apostles. They had, not yet broke in on the Church at Ephesus.

Scofield Reference Notes

Margin wolves

The two sources of the apostasy: false teachers from without, 2Cor 11:13-15 2Pet 2:1-3 ambitious leaders from within, 3Jn 1:9,10 Rev 2:6,15. Also, 1Tim 1:20 1Jn 2:19.

Jamieson-Fausset-Brown Bible Commentary

29, 30. after my departing shall grievous wolves enter in among you-Two classes of coming enemies are here announced, the one more external to themselves, the other bred in the bosom of their own community; both were to be teachers, but the one, "grievous wolves," not sparing, that is, making a prey of the flock; the other (Ac 20:30), simply sectarian "perverters" of the truth, with the view of drawing a party after them. Perhaps the one pointed to that subtle poison of Oriental Gnosticism which we know to have very early infected the Asiatic churches; the other to such Judaizing tendencies as we know to have troubled nearly all the early churches. See the Epistles to the Ephesians, Colossians, and Timothy, also those to the seven churches of Asia (Re 2:1-3:22). But watchfulness against all that tends to injure and corrupt the Church is the duty of its pastors in every age.

Matthew Henry's Concise Commentary

20:28-38 If the Holy Ghost has made ministers overseers of the flock, that is, shepherds, they must be true to their trust. Let them consider their Master's concern for the flock committed to their charge. It is the church He has purchased with his own blood. The blood was his as Man; yet so close is the union between the Divine and human nature, that it is there called the blood of God, for it was the blood of Him who is God. This put such dignity and worth into it, as to ransom believers from all evil, and purchase all good. Paul spake about their souls with affection and concern. They were full of care what would become of them. Paul directs them to look up to God with faith, and commends them to the word of God's grace, not only as the foundation of their hope and the fountain of their joy, but as the rule of their walking. The most advanced Christians are capable of growing, and will find the word of grace help their growth. As those cannot be welcome guests to the holy God who are unsanctified; so heaven would be no heaven to them; but to all who are born again, and on whom the image of God is renewed, it is sure, as almighty power and eternal truth make it so. He recommends himself to them as an example of not caring as to things of the present world; this they would find help forward their comfortable passage through it. It might seem a hard saying, therefore Paul adds to it a saying of their Master's, which he would have them always remember; It is more blessed to give than to receive: it seems they were words often used to his disciples. The opinion of the children of this world, is contrary to this; they are afraid of giving, unless in hope of getting. Clear gain, is with them the most blessed thing that can be; but Christ tell us what is more blessed, more excellent. It makes us more like to God, who gives to all, and receives from none; and to the Lord Jesus, who went about doing good. This mind was in Christ Jesus, may it be in us also. It is good for friends, when they part, to part with prayer. Those who exhort and pray for one another, may have many weeping seasons and painful separations, but they will meet before the throne of God, to part no more. It was a comfort to all, that the presence of Christ both went with him and stayed with them.