The psalmist, being struck with amazement at the wonderful works that God had done for his people, is strangely carried out here to foretel that work of wonder which excels all the rest and is the foundation and fountain of all, that of our redemption by our Lord Jesus Christ. God's thoughts, which were to us-ward concerning that work, were the most curious, the most copious, the most gracious, and therefore to be most admired. This paragraph is quoted by the apostle (Heb 10:5, etc.) and applied to Christ and his undertaking for us. As in the institutions, so in the devotions, of the Old Testament saints were aware of; and, when the apostle would show us the Redeemer's voluntary undertaking of his work, he does not fetch his account out of the book of God's secret counsels, which belong not to us, but from the things revealed. Observe,

I.The utter insufficiency of the legal sacrifices to atone for sin in order to our peace with God and our happiness in him: Sacrifice and offering thou didst not desire; thou wouldst not have the Redeemer to offer them. Something he must have to offer, but not these (Heb 8:3); therefore he must not be of the house of Aaron, Heb 7:14. Or, In the days of the Messiah burnt-offering and sin-offering will be no longer required, but all those ceremonial institutions will be abolished. But that is not all: even while the law concerning them was in full force it might be said, God did not desire them, nor accept them, for their own sake. They could not take away the guilt of sin by satisfying God's justice. The life of a sheep, which is so much inferior in value to that of a man (Mat 12:12), could not pretend to be an equivalent, much less an expedient to preserve the honour of God's government and laws and repair the injury done to that honour by the sin of man. They could not take away the terror of sin by pacifying the conscience, nor the power of sin by sanctifying the nature; it was impossible, Heb 9:9; Heb 10:1-4. What there was in them that was valuable resulted from their reference to Jesus Christ, of whom they were types - shadows indeed, but shadows of good things to come, and trials of the faith and obedience of God's people, of their obedience of God's people, of their obedience to the law and their faith in the gospel. But the substance must come, which is Christ, who must bring that glory to God and that grace to man which it was impossible those sacrifices should ever do.

II.The designation of our Lord Jesus to the work and office of Mediator: My ears hast thou opened. God the Father disposed him to the undertaking (Isa 50:5, Isa 50:6) and then obliged him to go through with it. My ear hast thou digged. It is supposed to allude to the law and custom of binding servants to serve for ever by boring their ear to the doorpost; see Exo 21:6. Our Lord Jesus was so in love with his undertaking that he would not go out free from it, and therefore engaged to persevere for ever in it; and for this reason he is able to save us to the uttermost, because he has engaged to serve his Father to the uttermost, who upholds him in it, Isa 42:1.

III.His own voluntary consent to this undertaking: "Then said I, Lo, I come; then, when sacrifice and offering would not do, rather than the work should be undone; I said, Lo, I come, to enter the lists with the powers of darkness, and to advance the interests of God's glory and kingdom." This intimates three things: - 1. That he freely offered himself to this service, to which he was under no obligation at all prior to his own voluntary engagement. It was no sooner proposed to him than, with the greatest cheerfulness, he consented to it, and was wonderfully well pleased with the undertaking. Had he not been perfectly voluntary in it, he could not have been a surety, he could not have been a sacrifice; for it is by this will (this animus offerentis - mind of the offerer) that we are sanctified, Heb 10:10. 2. That he firmly obliged himself to it: "I come; I promise to come in the fulness of time." And therefore the apostle says, "It was when he came into the world that he had an actual regard to this promise, by which he had engaged his heart to approach unto God." He thus entered into bonds, not only to show the greatness of his love, but because he was to have the honour of his undertaking before he had fully performed it. Though the price was not paid, it was secured to be paid, so that he was the Lamb slain from the foundation of the world. 3. That he frankly owned himself engaged: He said, Lo, I come, said it all along to the Old Testament saints, who therefore knew him by the title of ho erchomenos - He that should come. This word was the foundation on which they built their faith and hope, and which they looked and longed for the accomplishment of.

IV.The reason why he came, in pursuance of his undertaking - because in the volume of the book it was written of him, 1. In the close rolls of the divine decree and counsel; there it was written that his ear was opened, and he said, Lo, I come; there the covenant of redemption was recorded, the counsel of redemption was recorded, the counsel of peace between the Father and the Son; and to that he had an eye in all he did, the commandment he received of his Father. 2. In the letters patent of the Old Testament. Moses and all the prophets testified of him; in all the volumes of that book something or other was written of him, which he had an eye to, that all might be accomplished, Joh 19:28.

V.The pleasure he took in his undertaking. Having freely offered himself to it, he did not fail, nor was discouraged, but proceeded with all possible satisfaction to himself (Psa 40:8. 9): I delight to do thy will, O my God! It was to Christ his meat and drink to go on with the work appointed to him (Joh 4:34); and the reason here given is, Thy law is within my heart; it is written there, it rules there. It is meant of the law concerning the work and office of the Mediator, what he was to do and suffer; this law was dear to him and had an influence upon him in his whole undertaking. Note, When the law of God is written in our hearts our duty will be our delight.

VI.The publication of the gospel to the children of men, even in the great congregation, Psa 40:9, Psa 40:10. The same that as a priest wrought out redemption for us, as a prophet, by his own preaching first, then by his apostles, and still by his word and Spirit, makes it know to us. The great salvation began to be spoken by the Lord, Heb 2:3. It is the gospel of Christ that is preached to all nations. Observe, 1. What it is that is preached: It is righteousness (Psa 40:9), God's righteousness (Psa 40:10), the everlasting righteousness which Christ has brought in (Dan 9:24); compare Rom 1:16, Rom 1:17. It is God's faithfulness to his promise, and the salvation which had long been looked for. It is God's lovingkindness and his truth, his mercy according to his word. Note, In the work of our redemption we ought to take notice how brightly all the divine attributions shine, and give to God the praise of each of them. 2. To whom it is preached - to the great congregation, Psa 40:9 and again Psa 40:10. When Christ was here on earth he preached to multitudes, thousands at a time. The gospel was preached both to Jews and Gentiles, to great congregations of both. Solemn religious assemblies are a divine institution, and in them the glory of God, in the face of Christ, ought to be both praised to the glory of God and preached for the edification of men. 3. How it is preached - freely and openly: I have not refrained my lips; I have not hid it; I have not concealed it. This intimates that whoever undertook to preach the gospel of Christ would be in great temptation to hide it and conceal it, because it must be preached with great contention and in the face of great opposition; but Christ himself, and those whom he called to that work, set their faces as a flint (Isa 50:7) and were wonderfully carried on in it. It is well for us that they were so, for by this means our eyes come to see this joyful light and our ears to hear this joyful sound, which otherwise we might for ever have perished in ignorance of.

I have not not hid thy righteousness within my heart,.... Meaning not the essential righteousness of God, though that was abundantly declared in the wounds, sufferings, and death of Christ; and which was the end indeed of his being a propitiation for sin, Rom 3:25; but his own righteousness, as before, which he wrought out, and brought in; and which is called the righteousness of God his Father, because it is approved of by him, and accepted with him, and which he imputes to all his people;

I have declared thy faithfulness and thy salvation: trial is, the "faithfulness" of God in executing all his purposes, counsels, and decrees, which are said to be faithfulness and truth; and in fulfilling his covenant and promises, relating to the redemption and salvation of men by Christ; and in the mission of Christ into this world on that account; and in the accomplishment of all the prophecies of the Old Testament concerning him; and in making good all the particular promises of support, help, and strength, made to the Messiah himself: and by his "salvation" is meant, that which is of God the Father's appointing, continuing, and settling, in the council and covenant of grace; which he sent his Son to be the author of, and which he has obtained; and is the great doctrine of the Gospel preached by himself, and his faithful ministers, Luk 19:9;

I have not concealed thy lovingkindness and thy truth from the great congregation; or "in the great congregation", as the Targum. By the "lovingkindness" of God is designed both his love to Christ, which was before the foundation of the world, and continued in his lowest state of humiliation, and which our Lord was far from concealing, but gave openly instances of it, Joh 17:24; and this love to his people; and which he declared to be the same with that which he is loved with, and instances in the gift of himself to them by his Father, as the great evidence of it, Joh 17:23; and by "truth" is intended the Gospel in general, which came by Christ, was preached by him, which he bore witness to, to do which was one end of his coming into the world; and this was not concealed by him, who is truth itself; but was fully and plainly declared by him, as it had not been before, Joh 1:17.

I have preached--literally, "announced good tidings." Christ's prophetical office is taught. He "preached" the great truths of God's government of sinners.