Acts 20:28-31

Be careful for yourselves and for all the people the Holy Spirit has given to you to oversee. You must be like shepherds to the church of God, which he bought with the death of his own son. I know that after I leave, some people will come like wild wolves and try to destroy the flock. Also, some from your own group will rise up and twist the truth and will lead away followers after them. So be careful! Always remember that for three years, day and night, I never stopped warning each of you, and I often cried over you.