1 Samuel 18:5-9

5Whatever mission Saul sent him on, David was so successful that Saul gave him a high rank in the army. This pleased all the troops, and Saul’s officers as well. 6When the men were returning home after David had killed the Philistine, the women came out from all the towns of Israel to meet King Saul with singing and dancing, with joyful songs and with timbrels and lyres.

7As they danced, they sang: “Saul has slain his thousands, and David his tens of thousands.” 8Saul was very angry; this refrain displeased him greatly. “They have credited David with tens of thousands,” he thought, “but me with only thousands. What more can he get but the kingdom?”

9And from that time on Saul kept a close eye on David.