1 Samuel 10:7

19. These indeed are the signs by which a preacher may recognize himself, and then let him dare to undertake everything he plans to do, when he has learned by certain experience that he has received the power of the Holy Spirit in great abundance of charity. But the preacher ought to teach those things which he does, just as Luke says of the Lord: "That Jesus began to do and to teach, until the day in which, commanding the apostles through the Holy Spirit whom He had chosen, He was taken up" (Acts 1:1-2). Hence Paul says: "I dare not speak of those things which Christ has not accomplished through me, for the obedience of the Gentiles, by word and deed" (Rom. 15:18). And so Samuel commands the anointed king, saying: "Do whatever your hand finds to do." As if to say: When you see yourself filled with divine grace, teach others whatever you do, because from the divine grace presiding over you, you have the ability both to live excellently and to preach profitably.