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 10:9
Surrounding context
10:8 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."
10:9 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.
10:10 When they came there to the hill, there was a group of prophets to meet him; then the Spirit of God came upon him, and he prophesied among them.