1 Samuel 16:14

God had graciously given Saul His Spirit so that he could work as a king should. But Saul had rebelled against God's word. He thought he had every right to act on his own, apart from God. Therefore God removed His Spirit from him, to allow him to go ahead and act in his independent way.

Evil as well as good has its commission from God — not its existence, but its liberty to act, and the limits of its action. So we see with Job in early times, and in Ahab's case later; and it is a real comfort to know this. This is how the wrath of man is made to praise Him, and the rest of it He restrains. Nothing can escape from the divine government by the fact of being evil, or by admitting that it is. How could it? Only on this basis can we be at peace, sure that no waves can rise higher than the footstool of His throne.

God did more than let Saul take his own headstrong way. Saul had refused the Spirit of God, so he lay open to the opposite of this — an evil spirit. God allowed the evil spirit to trouble Saul to wake him to the folly of his own self-will. Disobedience to God does not leave us in a merely negative state, but in a state of positive evil. This sobering fact should have driven Saul to seek the grace of God. He should have handed his kingdom over willingly to the man God had chosen. Instead he kept stubbornly on in his evil course until his tragic death.

This seems to be a clearly marked case of demon possession. One who has rejected the word of God is given over to the power of Satan… Of the nature of that affliction, we cannot speak in detail. Without question, there was a sense of being forsaken by God, no longer having His approval. No one could fully describe the utter hopelessness and despair of this. Along with it there was likely some clouding of the mind, or at least an oppression that left him unfit for any duty. Some have said that King Saul was suffering from insanity. That is not the truth. It was not insanity, but the demon of evil to which he had yielded himself, and which now asserts itself as his master.

As soon as David is called to the throne, Saul's moral condition changes completely. Until that day the Spirit of God had been with the king according to the flesh. That is what explains each of Saul's successes against the enemies of Israel. Now the Spirit of the Lord comes upon David (v. 13) and departs from Saul, who is left in the power of "a harmful spirit from the LORD" (v. 14). This is a judgment from God, a chastisement on the king… At the same time God shows that His Spirit alone can lift up and drive away the evil spirit. We see it when David takes a harp and plays it before Saul.

Needless to say, the Holy Spirit comes to a believer once and once only. He comes, as our Lord said near the end of His life on earth, "to be with you forever" (John 14:16). Old Testament times were different. Then the Spirit might come and go — for instance, when "the Spirit of the LORD departed from Saul" (1 Sam. 16:14). Ephesians 4:30 agrees. It tells believers, "you were sealed for the day of redemption."