Acts 20:29-31 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.
This Paul preached and prophesied before going to Jerusalem and being arrested. This he said before he gave us all those great epistles that form the framework of how the body of Christ needs to operate in unity of faith.
2 Timothy 4:3 For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears;
As he predicted in Acts 20, “by the space of three years I ceased not to warn every one”. Paul is a little more specific here in 2nd Timothy as to the methods of the wolf. They feed the flock a steady diet which is pleasing to the ears but unhealthy for healing and unity of faith.
I will cut this short by leaving you one thought provoking comment that should help you identify the wolves in the world churches today.
Acts 20:33 I have coveted no man’s silver, or gold, or apparel.