It happened on the next day, that an evil spirit from God came mightily on Saul, and he prophesied in the midst of the house: and David played with his hand, as he did day by day. Saul had his spear in his hand;
Of course, he was not aware of the fact that God had chosen David to be the king, and that God had anointed David to be king over Israel. So it is interesting that immediately he began to suspicion the fact that the kingdom was in jeopardy. "What does he want more than this, the kingdom?"