1 Samuel 16:15

Hardly is David called to the throne when Saul's moral condition changes completely. Until that day the Spirit of God had been with the king according to the flesh, and this 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 "an harmful spirit from the LORD" (v. 14). This is a judgment from God, a chastisement upon the king.

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 remainder of it He restrains. Nothing can escape from the divine government by the fact or the claim of being evil. How could it? Only in this way can we be at peace, sure that no waves can rise higher than the footstool of His throne.

A "messenger of Satan" may be sent out from the presence of God upon either the flesh or the heart of man. An evil spirit from the Lord came upon Saul, and a lying spirit came upon the prophets of Ahab. The Lord was beginning solemn acts of judgment, and so these messengers of Satan were sent out upon the heart of those who were rightly under judgment. But other messengers of Satan reach only the body or the circumstances, as with Paul and our patriarch. And this is discipline only, and not judgment.

God allowed Saul to take his own headstrong way. More than that: since Saul had refused the Spirit of God, he lay open to the opposite, an evil spirit. God let that evil spirit trouble Saul, to wake him up 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.

It has sometimes been said that king Saul was afflicted with insanity. This is not the truth. Sadly, it was not insanity, but the demon of evil to which he had yielded himself and which now asserts itself as his master.

The desire of Saul, the rejected king, was not a godly one; he should have looked in his own conduct for the cause of his trouble.

David's harp does not act directly on Satan, but on Saul. It has a strange power to soften and subdue the savage temper of the rejected king, though only for a time. By that means it drives back the power attacking him and shuts it out. For the time, he is set free.

There is a solemn thought here. Some ministry of Christ is so soothing that it can partly relieve a soul's fears and distress without working any real cure. David is clearly a type of Christ here. By His Spirit, Christ ministers His word in the ordinary way — its sweet story of God's love and care, of His power over evil, of the comfort He brings to His own. That word gives relief even to those whose hearts are estranged from God.