“And Saul sought to smite David even to the wall with the javelin; but he slipped away out of Saul's presence, and he smote the javelin into the wall: and David fled, and escaped that night.”
King James Version (KJV)
19:8 And David, &c. - So David continues his good service, tho' it was ill requited. They who are ill paid for doing good, yet must not be weary of well doing, remembering how bountiful a benefactor God is, even to the evil and unthankful.
19:9 The evil spirit - David's successes against the Philistines revived his envy, and the devil watched the opportunity, as he had done before.