An evil spirit. — Whether the word used for spirit (ruach) is here meant to be personal or not we cannot say. Sometimes it seems to mean an evil being (1 Samuel 16:14), sometimes only an evil temper (Numbers 14:24). The later Jews would have made little or no difference between the two, since they attributed almost every evil to the direct agency of demons.
Dealt treacherously. — The word is used for the beginning of a defection.