I Samuel 10:5-9

After that you shall come to the hill of God where the Philistine garrison is. And it will happen, when you have come there to the city, that you will meet a group of prophets coming down from the high place with a stringed instrument, a tambourine, a flute, and a harp before them; and they will be prophesying. Then the Spirit of the LORD will come upon you, and you will prophesy with them and be turned into another man. And let it be, when these signs come to you, that you do as the occasion demands; for God is with you. You shall go down before me to Gilgal; and surely I will come down to you to offer burnt offerings and make sacrifices of peace offerings. Seven days you shall wait, till I come to you and show you what you should do.” So it was, when he had turned his back to go from Samuel, that God gave him another heart; and all those signs came to pass that day.