The “evil” or “melancholy” spirit here spoken of was “the Spirit of God,” or “of Jehovah,” as being God’s messenger and minister, sent by Him to execute His righteous purpose upon Saul (see 1 Kings 22:19-22 note).
Related Commentaries of 1 Samuel 16:15
1 Samuel 16:15
15 And Saul's servants said unto him, Behold now, an evil spirit from God troubleth thee.