15. He hath digged a pit, and hollowed it out; and he hath fallen into the ditch which he hath made.16. His wickedness shall return upon his own head, and his violence shall descend upon his own crown.
Here David says not only that their wicked devices were without success, but that, by the wonderful providence of God, the result was the very opposite of what had been contemplated. He sets this forth in the first place metaphorically, by employing the figure of a pit and a ditch; and then he expresses the same thing in simple terms without figure, declaring, that the mischief intended for others returned upon the head of him who had devised it There is no doubt that it was a common proverb among the Jews, He who hath digged a pit falleth into it; which they quoted when they meant to say, that wicked and crafty men are caught in the snares and traps which they have set for others, or that the contrivers of the ruin of others perish by their own devices. There is a twofold use of this doctrine: the first place, however skilled in craft our enemies may be, and whatever means of doing mischief they may have, we must nevertheless look for the issue which God here promises, that they shall fall by their own sword. And this is not a thing which happens by chance; but God, by the secret direction of his own hand, causes the evil which they intend to bring upon the innocent to return upon their own heads. In the second place, If at any time we are instigated by passion to inflict any injury upon our neighbours, or to commit any wickedness, let us remember this principle of retributive justice, which is often acted upon by the divine government, that those who prepare a pit for others are cast into it themselves; and the effect will be, that every one, in proportion as he would consult his own happiness and welfare, will be careful to restrain himself from doing any injury, even the smallest, to another.
17 I will praise Jehovah according to his righteousness; and I will sing to the name of Jehovah, Most High As the design of God in the deliverances which he vouchsafes to his servants is, that they may render to him in return the sacrifices of praise, David here promises that he will gratefully acknowledge the deliverance which he had received, and at the same time affirms that his preservation from death was the undoubted and manifest work of God. He could not, with truth, and from the heart, have ascribed to God the praise of his deliverance, if he had not been fully persuaded that he had been preserved otherwise than by the power of man. He, therefore, not only promises to exercise the gratitude which was due to his deliverer, but he confirms in one word what he has rehearsed throughout the psalm, that he is indebted for his life to the grace of God, who had not suffered Saul to take it from him. The righteousness of God is here to be understood of his faithfulness which he makes good to his servants in defending and preserving their lives. God does not shut up or conceal his righteousness from our view in the secret recesses of his own mind, but manifests it for our advantage when he defends us against all wrongful violence, delivers us from oppression, and preserves us in safety although wicked men make war upon us and persecute us.