Then Samuel took a flask of oil and poured it on his head, and kissed him and said: “Is it not because the Lord has anointed you commander over His inheritance? When you have departed from me today, you will find two men by Rachel’s tomb in the territory of Benjamin at Zelzah; and they will say to you, ‘The donkeys which you went to look for have been found. And now your father has ceased caring about the donkeys and is worrying about you, saying, “What shall I do about my son?”’ Then you shall go on forward from there and come to the terebinth tree of Tabor. There three men going up to God at Bethel will meet you, one carrying three young goats, another carrying three loaves of bread, and another carrying a skin of wine. And they will greet you and give you two loaves of bread, which you shall receive from their hands. 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.
-1 Samuel 10:1-9