My son hath made a league with the son of Jesse: this he suspected, partly from Jonathan's passionate love for David, which he had formerly and constantly declared; and from his late discontent and departure from his father, mentioned 1 Samuel 20:34; and partly from David's confidence, in invading the land with four hundred men, which he thought he would never presume to do, without some encouragement or promise of assistance from Jonathan. To lie in wait, i.e. to design against my crown and life (which will appear to be a most groundless suspicion and false accusation).
Related Commentaries of 1 Samuel 22:8
1 Samuel 22:8
8 That all of you have conspired against me, and there is none that shewethb me that my son hath made a league with the son of Jesse, and there is none of you that is sorry for me, or sheweth unto me that my son hath stirred up my servant against me, to lie in wait, as at this day?