וְר֧וּחַ יְהוָ֛ה סָ֖רָה מֵעִ֣ם שָׁא֑וּל וּבִֽעֲתַ֥תּוּ רֽוּחַ־רָעָ֖ה מֵאֵ֥ת יְהוָֽה׃
Now the spirit of the LORD had departed from Saul, and an evil spirit from the LORD terrified him.
Read kabbalistic (mystical) interpretation of I Samuel 16:14: and classical mystical sources.