1 Samuel 18:7
And the women answered one another as they played, and said, Saul hath slain his thousands, and David his ten thousands. And the women answered one another as they played, and said, Saul hath slain his thousands, and David his ten thousands.
The verse records the women's song celebrating Israel's victory over the Philistines as Saul and David returned from battle. It was sung responsively, with one group crediting Saul with slaying thousands and another crediting David with slaying ten thousands. Its wording honored David more highly than Saul by contrasting thousands slain with ten thousands slain, and the praise given to David showed how greatly the people esteemed him.
Saul heard the comparison as a threat to his standing, taking the greater praise of David as a sign that David might take the kingdom. His desire for human praise turned the song into an occasion for jealousy and anger, and his fear and hatred grew.
The verse became a well-known dance-song in Israel that identified David as the nation's celebrated warrior, and the Philistine lords knew it and quoted it. They associated the song in memory with the killing of their famed champion and with Israel's triumph on that occasion. They used the song as proof that David would not fight against his own people but would turn against the Philistines in battle to win back Saul's favor at the cost of Philistine lives.