Then Saul ordered his son Jonathan and all his servants to kill David. But Jonathan delighted greatly in David,

1 Samuel 18:1
After David had finished speaking with Saul, the souls of Jonathan and David were knit together, and Jonathan loved him as himself.

1 Samuel 18:8
And Saul was furious and resented this song. "They have ascribed tens of thousands to David," he said, "but only thousands to me. What more can he have but the kingdom?"

1 Samuel 18:9
And from that day forward Saul kept a jealous eye on David.

1 Samuel 19:2
so he warned David, saying, "My father Saul intends to kill you. Be on your guard in the morning; find a secret place and hide there.

And Saul spoke to Jonathan his son, and to all his servants, that they should kill David.