Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God, which he hath purchased with his own blood.
For I know this, that after my departing shall grievous wolves enter in among you, not sparing the flock.
Also of your own selves shall men arise, speaking perverse things, to draw away disciples after them.
Therefore watch, and remember, that by the space of three years I ceased not to warn every one night and day with tears.
Acts 20: 28-31