1 Samuel 19:1

And Saul speaketh unto Jonathan his son, and unto all his servants, to put David to death,

1 Samuel 18:1

And it cometh to pass, when he finisheth to speak unto Saul, that the soul of Jonathan hath been bound to the soul of David, and Jonathan loveth him as his own soul.

1 Samuel 18:9

and Saul is eyeing David from that day and thenceforth.

Treasury of Scripture Knowledge

Summary

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

Bible References

And saul

Ecclesiastes 9:3
This is an evil among all that hath been done under the sun, that one event is to all, and also the heart of the sons of man is full of evil, and madness is in their heart during their life, and after it -- unto the dead.
Jeremiah 9:3
And they bend their tongue, their bow is a lie, And not for stedfastness have they been mighty in the land, For from evil unto evil they have gone forth, And Me they have not known, An affirmation of Jehovah!
2 Timothy 3:13
and evil men and impostors shall advance to the worse, leading astray and being led astray.