AndtheevilspiritfromtheLord - His envy and jealousy again returned, producing distraction of mind, which was exacerbated by diabolic influence. See on 1 Samuel 16:14; (note).
Matthew Henry
Concise Bible Commentary
How forcible are right words! Saul was, for a time, convinced of the unreasonableness of his enmity to David; but he continued his malice against David. So incurable is the hatred of the seed of the serpent against that of the woman; so deceitful and desperately wicked is the heart of man without the grace of God, Jer 17:9.
SDA Bible Commentary (limited)
Volume 1-7
9. The evil spirit. See on ch.16:14, 15. The devil had known ever since the time of David’s anointing that he was being trained for kingship. Hence the evil one might be expected to attempt to thwart God’s plan. He could have conceived no more effective means of doing so than by convincing Saul that David sought to usurp the kingdom.