Charles Ellicott Commentary 1 Samuel 18:12

"And Saul was afraid of David, because Jehovah was with him, and was departed from Saul." — 1 Samuel 18:12 (ASV)

And Saul was afraid of David. —Even after the scenes in the royal chamber just related, David remained at Court. He looked on such manifestations of bitter hatred as simple outbursts of a temporary insanity. His loyal nature would not believe in the enduring hate of one so great and noble as Saul; but we read here that even when the king recovered from the paroxysm, he feared David.

Saul was conscious that his old vigor and ability were deserting him, and in David he recognized the presence of a power he knew had once been his. Not being able, even in his sane hours, to endure the presence of one whom he felt all too surely would sooner or later take his place, the king dismissed him honorably from the Court, and invested him with an important military charge. Perhaps already the dark thought which some time later (see 1 Samuel 18:17, 25) influenced the king had entered his unhappy mind.