The psalmist has a very sad complaint to make of the deplorable condition of the family of David at this time, and yet he begins the psalm with songs of praise; for we must, in every thing, in every state, give thanks; thus we must glorify the Lord in the fire. We think, when we are in trouble, that we get ease by complaining; but we do more - we get joy, by praising. Let our complaints therefore be turned into thanksgivings; and in these verses we find that which will be matter of praise and thanksgiving for us in the worst of times, whether upon a personal or a public account, 1. However it be, the everlasting God is good and true, Psa 89:1. Though we may find it hard to reconcile present dark providences with the goodness and truth of God, yet we must abide by this principle, That God's mercies are inexhaustible and his truth is inviolable; and these must be the matter of our joy and praise: "I will sing of the mercies of the Lord for ever, sing a praising song to God's honour, a pleasant song for my own solace, and Maschil, an instructive song, for the edification of others." We may be for ever singing God's mercies, and yet the subject will not be drawn dry. We must sing of God's mercies as long as we live, train up others to sing of them when we are gone, and hope to be singing them in heaven world without end; and this is singing of the mercies of the Lord for ever. With my mouth, and with my pen (for by that also do we speak), will I make known thy faithfulness to all generations, assuring posterity, from my own observation and experience, that God is true to every word that he has spoken, that they may learn to put their trust in God, Psa 78:6. 2. However it be, the everlasting covenant is firm and sure, Psa 89:2-4. Here we have, (1.) The psalmist's faith and hope: "Things now look black, and threaten the utter extirpation of the house of David; but I have said, and I have warrant from the word of God to say it, that mercy shall be built up for ever." As the goodness of God's nature is to be the matter of our song (Psa 89:1), so much more the mercy that is built for us in the covenant; it is still increasing, like a house in the building up, and shall still continue our rest for ever, like a house built up. It shall be built up for ever; for the everlasting habitations we hope for in the new Jerusalem are of this building. If mercy shall be built for ever, then the tabernacle of David, which has fallen down, shall be raised out of its ruins, and built up as in the days of old, Amo 9:11. Therefore mercy shall be built up for ever, because thy faithfulness shalt thou establish in the very heavens. Though our expectations are in some particular instances disappointed, yet God's promises are not disannulled; they are established in the very heavens (that is, in his eternal counsels); they are above the changes of this lower region and out of the reach of the opposition of hell and earth. The stability of the material heavens is an emblem of the truth of God's word; the heavens may be clouded by vapours arising out of the earth, but they cannot be touched, they cannot be changed. (2.) An abstract of the covenant upon which this faith and hope are built: I have said it, says the psalmist, for God hath sworn it, that the heirs of promise might be entirely satisfied of the immutability of his counsel. He brings in God speaking (Psa 89:3), owning, to the comfort of his people, "I have made a covenant, and therefore will make it good." The covenant is made with David; the covenant of royalty is made with him, as the father of his family, and with his seed through him and for his sake, representing the covenant of grace made with Christ as head of the church and with all believers as his spiritual seed. David is here called God's chosen and his servant; and, as God is not changeable to recede from his own choice, so he is not unrighteous to cast off one that served him. Two things encourage the psalmist to build his faith on this covenant: - [1.] The ratification of it; it was confirmed with an oath: The Lord has sworn, and he will not repent. [2.] The perpetuity of it; the blessings of the covenant were not only secured to David himself, but were entailed on his family; it was promised that his family should continue - Thy seed will I establish for ever, so that David shall not want a son to reign (Jer 33:20, Jer 33:21); and that it should continue a royal family - I will build up thy throne to all generations, to all the generations of time. This has its accomplishment only in Christ, of the seed of David, who lives for ever, to whom God has given the throne of his father David, and of the increase of whose government and peace there shall be no end. Of this covenant the psalmist will return to speak more largely, Psa 89:19, etc.

Thy seed will I establish for ever,.... Meaning not the natural seed of David, at least not only them; whose family was indeed preserved, though in very low circumstances, until the Messiah came, who sprung from thence, Luk 1:27, but the spiritual seed of Christ, to whom it was promised that he should have a seed, and should see and enjoy it, and which should endure for ever; see Psa 89:29, and so he always has had a seed to serve him in all generations, in the worst of times, and will; and who are established in him, and will be kept and preserved by him, and whom he will present to his Father, saying, "Lo, I and the children whom thou hast given me", Heb 2:13.

and build up thy throne to all generations; and this shows that the passage is not to be understood literally of David, and of his temporal throne and kingdom, which did not last many generations; but of the spiritual throne and kingdom of the Messiah, who sprung from him, called the throne of his father David, whose throne is for ever and ever, and whose kingdom is an everlasting kingdom, Luk 1:32, Psa 45:6, his throne is in the heavens, where he will reign until all enemies are put under his feet; and it is also in the midst of his church, and in the hearts of his people, where he reigns as King of saints; and he is on the same throne with his Father; it is the same with his, as to glory, power, and authority; on this he will sit, and judge the world at the last day; and on it he will reign with his people a thousand years, in the New Jerusalem state, and after that to all eternity, Rev 3:21.

Selah. See Gill on Psa 3:2.