24 My truth and my mercy shall be with him. God shows that he will continue to exercise without intermission that grace which he had manifested towards David at first. These words are as if he had said, that to prove himself faithful to his word, he would be always gracious and bountiful. Thus We see that God, not only at the outset, furnished David with testimonies of his goodness, but that he always continued to deal with him in the same merciful way. This has a reference to the whole Church of Christ, so that the divine goodness is manifested in the whole course of our salvation, and not only at our first entrance upon it, as these shufflers and sophists the Sorbonists foolishly talk. ⁵⁴³⁵⁴³     “I will make him my first-born; i.e., as the eldest son of a family ranks the highest, and receives the most from his father, so shall David be first in the order of kings, who, when they are legitimate sovereigns, may be regarded as the sons of God, their common Father: comp. Genesis 27:1, etc.; Exodus 4:22; Deuteronomy 21:17; Psalm 2:7; Colossians 1:15. In Isaiah 14:30, by the first-born of the poor, is meant the extreme of that class, they who are the poorest of the poor.” — Cresswell. The horn of David denotes here, as it often does in other places, his glory, dignity, and power. The meaning therefore is, that by the grace of God, this kingdom shall always flourish and prosper.

25. And I will set his hand in the sea. The vast extent of the kingdom is here adverted to. As the people by their wickedness had, as it were, blocked up the way, and intercepted the blessing of God, their inheritance was more limited than the promise implied. But now God declares, that during the reign of David, it will be again enlarged, so that the people shall possess the whole country, from the sea even to the river Euphrates. From this we gather, that what God had promised by Moses was fulfilled only in the person of David, that is to say, from his time. ⁵⁴⁴⁵⁴⁴     “Sicuti nugantur Sophistae.” — Lat. “Comme gazouillent ces brouillons et Sophistes de Sorbonistes.” — Fr. By the rivers may be understood, either the Euphrates alone, which is cut into many channels, or the other neighboring rivers on the coast of Syria.

26. He shall cry to me, Thou art my Father. In this verse it is declared, that the chief excellence of this king will consist in this, that he will be accounted the Son of God. This indeed is a title of honor, which is applied to all whom God ordains to be kings, as we have seen in a previous psalm,

“I have said, Ye are gods; and all of you are children of the Most High:”
(Psalm 82:6)

but in the passage before us, something special is expressed of the holy king whom God had chosen, and it is intended to say, that he will be the son of God in a different sense. We shall immediately see in the subsequent verse, how he is placed in a higher rank than the kings of the earth, although they may sway the scepter over a larger extent of country. It was therefore a privilege peculiar to only one king in this world, to be called the Son of God. Had it been otherwise, the apostle reasoned not only inconclusively but absurdly, in quoting this text as a proof of the doctrine, that Christ is superior to the angels:

“I will be to him a Father, and he shall be to me a Son,”
(Hebrews 1:5.)

Angels, and kings, and all who are regenerated by the Spirit of adoption, are called sons of God; but David, when God promises to take him for his son, is, by singular prerogative, elevated above all others to whom this designation is applied. This is still more apparent from the following verse, in which he is called God’s first-born, because he is higher than all the kings of the earth; and this is an honor which transcends all the dignity both of men and angels. If it is objected, that David being a mortal man could not be equal to the angels, the obvious answer is, that if he is considered in himself, he cannot justly be elevated to the same rank with them, but with the highest propriety he may, in so far as for a time he represented the person of Christ.

28. And I will keep my mercy to him for ever. We see how God frequently repeats, that he had set up the kingdom of David with the express design of establishing it for ever. By placing his mercy first in order, and then adding his covenant, he points out the cause of this covenant, intimating in one word, that it is gratuitous, and that his grace is not only the foundation on which it rests, but also the cause why it is preserved inviolate. The amount is, that God will be always merciful to David, in order that his covenant may never fail. From this it follows, that its inviolability depends upon the mere good pleasure of God. In the next verse, God expresses the effect of his truth, declaring, that the posterity of David will sit for ever on the royal throne. There being nothing under heaven of long continuance, the days of heaven is an expression employed to denote everlasting duration. Whence it follows, that this prophecy cannot have its full accomplishment in any till we come to Christ, in whom alone, in the strict and proper sense, this everlasting duration is to be found.