This conclusion of the song speaks three things:
I. Glory to God, Deuteronomy 32:39. "See now upon the whole matter, that I, even I, am he. Learn this from the destruction of idolaters, and the inability of their idols to help them." The great God here demands the glory, 1. Of a self-existence: I, even I, am he. Thus Moses concludes with that name of God by which he was first made to know him (Exodus 3:14), "I am that I am. I am he that I have been, that I will be, that I have promised to be, that I have threatened to be; all shall find me true to my word." The Targum of Uzzielides paraphrases it thus: When the Word of the Lord shall reveal himself to redeem his people, he shall say to all people, See that I now am what I am, and have been, and I am what I will be, which we know very well how to apply to him who said to John, I am he who is, and was, and is to come, Revelation 1:8. These words, I even I, am he, we meet with often in those chapters of Isaiah where God is encouraging his people to hope for their deliverance out of Babylon, Isaiah 41:4. 2. Of a sole supremacy. "There is no god with me. None to help with me, none to cope with me." See Isaiah 43:10-11. 3. Of an absolute sovereignty, a universal agency: I kill, and I make alive; that is, all evil and all good come from his hand to providence; he forms both the light of life and the darkness of death, Isaiah 45:7. Or, He kills and wounds his enemies, but heals and makes alive his own people, kills and wounds with his judgments those that revolt from him and rebel against him; but, when they return and repent, he heals them, and makes them alive with his mercy and grace. Or it denotes his incontestable authority to dispose of all his creatures, and the beings he has given them, so as to serve his own purposes by them: Whom he will he slays, and whom he will he keeps alive, when his judgments are abroad. Or thus, Though he kill, yet he makes alive again: though he cause grief, yet will he have compassion, Lamentations 3:32. Though he have torn, he will heal us, Hosea 6:1-2. The Jerusalem Targum reads it, I kill those that are alive in this world, and make those alive in the other world that are dead. And some of the Jewish doctors themselves have observed that death, and a life after it, that is, eternal life, is intimated in these words. 4. Of an irresistible power, which cannot be controlled: Neither is there any that can deliver out of my hand those that I have marked for destruction. As no exception can be made against the sentence of God's justice, so no escape can be made from the executions of his power.
II. Terror to his enemies, Deuteronomy 32:40-42. Terror indeed to those that hate him, as all those do that serve other gods, that persist in wilful disobedience to the divine law, and that malign and persecute his faithful servants. These are those to whom God will render vengeance, those his enemies that will not have him to reign over them. In order to alarm such in time to repent and return to their allegiance, the wrath of God is here revealed from heaven against them. 1. The divine sentence is ratified with an oath (Deuteronomy 32:40): He lifts up his hand to heaven, the habitation of his holiness; this was an ancient and very significant sign used in swearing, Genesis 14:22. And, since he could swear by no greater, he swears by himself and his own life. Those are miserable without remedy that have the word and oath of God against them. The Lord hath sworn, and will not repent, that the sin of sinners shall be their ruin if they go on in it. 2. Preparation is made for the execution: The glittering sword is whet. See Psalm 7:12. It is a sword bathed in heaven, Isaiah 34:5. While the sword is in whetting, space is given to the sinner to repent and make his peace, which, if he neglects, will render the wound the deeper. And, as the sword is whet, so the hand that is to wield it takes hold on judgment with a resolution to go through with it. 3. The execution itself will be very terrible: The sword shall devour flesh in abundance, and the arrows be made drunk with blood, such vast quantities of it shall be shed, the blood of the slain in battle, and of the captives, to whom no quarter shall be given, but who shall be put under military execution. When he begins revenge he will make an end; for in this also his work is perfect. The critics are much perplexed with the last clause, From the beginning of revenges upon the enemy. The learned bishop Patrick (that great master) thinks it may admit this reading, From the king to the slave of the enemies, Jeremiah 50:35-37. When the sword of God's wrath is drawn it will make bloody work, blood to the horse-bridles, Revelation 14:20.
III. Comfort to his own people (Deuteronomy 32:43): Rejoice, O you nations, with his people. He concludes the song with words of joy; for in God's Israel there is a remnant whose end will be peace. God's people will rejoice at last, will rejoice everlastingly. Three things are here mentioned as the matter of joy:—1. The enlarging of the church's bounds. The apostle applies the first words of this verse to the conversion of the Gentiles. Romans 15:10, Rejoice you Gentiles with his people. See what the grace of God does in the conversion of souls, it brings them to rejoice with the people of God; for true religion brings us acquainted with true joy, so great a mistake are those under that think it tends to make men melancholy. 2. The avenging of the church's controversies upon her adversaries. He will make inquisition for the blood of his servants, and it shall appear how precious it is to him; for those that spilt it shall have blood given them to drink. 3. The mercy God has in store for his church, and for all that belong to it: He will be merciful to his land, and to his people, that is, to all everywhere that fear and serve him. Whatever judgments are brought upon sinners, it shall go well with the people of God; in this let Jews and Gentiles rejoice together.