By his knowledge of human nature and by experience, as well as by the light given him by the Spirit of God.

 Paul had been a guardian to the churches he had gathered together. Their danger would increase in his absence. So Israel was faithful during the days of Joshua and of the elders who outlived him (Judges 2:7), but afterward came apostasy.

 Here Paul is paralleling Christ’s allegory of the good shepherd. The hireling is no match for the wolf (John 10:12), but the true shepherd of the flock stands his ground in defense of the helpless sheep. Christ, knowing the acute danger of such attacks, warned of it (Matt. 7:15). The elders of Ephesus are to guard the sheep against the wolves that Paul foresees will enter from outside the sheepfold of the church. His warning to these elders does not stand alone. He had already written to the Thessalonians that a great apostasy was to come (2 Thess. 2:1-12), and wrote later to Timothy, alerting him to coming dangers of the same sort (1 Tim. 4:1-3; 2 Tim. 3:1-15). The apostle John, in the last moments of the first apostolic century, saw apostasy as a danger current in his day (1 John 4:1), and in the Revelation he relates visions he was given of appalling decay and paganizing of the church (Rev. 2:12-24; 6:3-11, 17; 18). See pp. 64-67.