1. I will sing of the mercies of Jehovah for ever. It must be borne in mind, as I have just now observed, that the Psalmist opens with the praises of God, and with calling to mind the Divine covenant, to encourage the faithful to strengthen their faith against the formidable assaults of temptation. If when we set about the duty of prayer some despairing thought, at the very outset, presents itself to us, we must forcibly and resolutely break through it, lest our hearts faint and utterly fail. The design of the prophet, therefore, was to fortify the minds of the godly at the very commencement, with stable and substantial supports, that, relying on the Divine promise, which, to outward appearance, had almost fallen to the ground, and repelling all the assaults of temptation with which their faith was severely shaken, they might with confidence hope for the re-establishment of the kingdom, and continue perseveringly to pray for this blessing. From the sad spectacle of begun decay,² which Ethan beheld, listening to the dictates of carnal reason, he might have thought that both himself and the rest of God's believing people were deceived; but he expresses his determination to celebrate the mercies of God which at that time were hidden from his view. And as it was no easy matter for him to apprehend and acknowledge the merciful character of God, of whose severity he had actual experience, he uses the plural number, the Mercies of God, that by reflecting on the abundance and variety of the blessings of Divine grace he might overcome this temptation.

2. For I have said, Mercy shall be built up for ever. He assigns the reason why he perseveres in singing the Divine praises in the midst of adversities; which is, that he does not despair of the manifestation of God's loving-kindness towards his people, although at present they were under severe chastisement. Never will a man freely open his mouth to praise God, unless he is fully persuaded that God, even when he is angry with his people, never lays aside his fatherly affection towards them. The words I have said, imply that the truth which the inspired writer propounds was deeply fixed in his heart.³ Whatever, as if he had said, has hitherto happened, it has never had the effect of effacing from my heart the undoubted hope of experiencing the Divine favor as to the future, and I will always continue steadfastly to cherish the same feeling. It is to be observed, that it was not without a painful and arduous conflict that he succeeded in embracing by faith the goodness of God, which at that time had entirely vanished out of sight; -- this we say is to be particularly noticed, in order that when God at any time withdraws from us all the tokens of his love, we may nevertheless learn to erect in our hearts that everlasting building of mercy, which is here spoken of, -- a metaphor, by which is meant that the Divine mercy shall be extended, or shall continue till it reach its end or consummation. In the second clause of the verse something must be supplied. The sense, in short, is, that the Divine promise is no less stable than the settled course of the heavens, which is eternal and exempt from all change. By the word heavens I understand not only the visible skies, but the heavens which are above the whole frame of the world; for the truth of God, in the heavenly glory of his kingdom, is placed above all the elements of the world.

3. I have made a covenant with my chosen.⁴ The more effectually to confirm himself and all the godly in the faith of the Divine promise, he introduces God himself as speaking and sanctioning, by his authority, what had been said in the preceding verse. As faith ought to depend on the Divine promise, this manner of speaking, by which God is represented as coming forward and alluring us to himself by his own voice, is more forcible than if the prophet himself had simply stated the fact. And when God in this way anticipates us, we cannot be charged with rashness in coming familiarly to him; even as, on the contrary, without His word we have no ground to presume that he will be gracious to us, or to hope, at the mere suggestion of our own fancy, for what he has not promised. Moreover, the truth of the promise is rendered still more irrefragable, when God declares that he had made a covenant with his servant David, ratified by his own solemn oath. It having been customary in ancient times to engrave leagues and covenants on tables of brass, a metaphor is here used borrowed from this practice. God applies to David two titles of distinction, calling him both his chosen and his servant. Those who would refer the former appellation to Abraham do not sufficiently attend to the style of the Book of Psalms, in which it is quite common for one thing to be repeated twice. David is called the chosen of God, because God of his own good pleasure, and from no other cause, preferred him not only to the posterity of Saul, and many distinguished personages, but even to his own brethren. If, therefore, the cause or origin of this covenant is sought for, we must necessarily fall back upon the Divine election.

The name of servant, which follows immediately after, is not to be understood as implying that David by his services merited any thing at the hand of God. He is called God's servant in respect of the royal dignity, into which he had not rashly thrust himself, having been invested with the government by God, and having undertaken it in obedience to his lawful call. When, however, we consider what the covenant summarily contains, we conclude that the prophet has not improperly applied it to his own use, and to the use of the whole people; for God did not enter into it with David individually, but had an eye to the whole body of the Church, which would exist from age to age. The sentence, I will establish thy throne for ever, is partly to be understood of Solomon, and the rest of David's successors; but the prophet well knew that perpetuity or everlasting duration, in the strict and proper sense, could be verified only in Christ. In ordaining one man to be king, God assuredly did not have a respect to one house alone, while he forgot and neglected the people with whom he had before made his covenant in the person of Abraham; but he conferred the sovereign power upon David and his children, that they might rule for the common good of all the rest, until the throne might be truly established by the advent of Christ.