Matthew Poole's Concise Commentary
Psalms 40:7
Then, when I understood and considered thy mind and will therein, expressed Psalms 40:6. Said I; either within myself, by a firm purpose; or unto thee by way of promise or engagement. Lo, I come. He may seem to speak like a servant, answering to the call of his master, and signifying his readiness to obey him; in which sense it may be accommodated to David. But the servant's answer is usually expressed in Scripture by another phrase, Here am I, and never to my remembrance in these words. Besides, this phrase in that sense seems not to be proper in this place, but rather, Lo, I hear, which best suits with the foregoing words, mine ears hast thou opened. But these words do most literally and truly belong to Christ, and the sense is this: Seeing thou requirest a better sacrifice than those of the law, lo, I do offer myself to come; and I will in due time come, to wit, from heaven, or in the flesh, or into the world, as this phrase is more fully expressed and explained in divers places of Scripture, and particularly Hebrews 10:5, where this place is explained and applied to Christ. The two words volume and book are indifferently used of any writing, and both words seem here to express the same thing, as may appear by comparing Jer 36 $, where we have the very same words; and what is called the roll or volume of a book, Jeremiah 36:2,4, is called simply a roll or volume, Jeremiah 36:6,20,21, and the book, Jeremiah 36:10,13; it being usual with the Hebrews to join two words together in like manner, of which we have an instance here above, Psalms 40:2, miry clay, Heb. clay of mire. Now this volume of the book, is meant, either,
1. Of the book of predestination, in which Christ was written, as being foreordained before the foundation of the world, 1 Peter 1:20. But that is a secret book, not to be read by any man living, and therefore not fitly alleged as an evidence in this matter. Or,
2. Of a legal instrument, wherein the contract was drawn between God and him, wherein he did oblige himself to serve God, and to execute his will in all things; it being the manner of the Hebrews to write their contracts in a little volume or book. But,
1. We read of no such usage among the Hebrew in the contracts between master and servant, but only of the boring of the servant's ear, Exodus 21:6. So the foundation of this allusion is destroyed.
2. At least there was no such contract written between God and him. And if it be said that he only speaks thus by way of allusion, that is but a supposition without ground. And when the words may be properly understood as they sound, of a thing really done, why should we forsake the plain sense without necessity?
3. The phrase here used doth not agree to this sense; for then he should have said, I am written in the volume of the book, i.e. in the catalogue of thy servants; for in that case the persons or their names are constantly said to be written, as Exodus 32:32,33 Psa 69:28 Daniel 12:1 Luke 10:20 Hebrews 12:23 Revelation 13:8, Revelation 20:15 21:27, and not any thing to be written of them, as it is here. Or,
3. Of the Holy Scriptures; in which something indeed was written concerning David; namely, that he was a man after God's own heart, 1 Samuel 13:14. But it must be remembered that those books were not written till after David's death, in whose time here was no other book of Scripture extant but the five books of Moses, unless you will except the book of Job. And therefore this is meant of the law of Moses, which is commonly and emphatically called the book, and was made up in the form of a roll or volume, as the Hebrew books generally were. See Ezekiel 3:1 Malachi 5:1,2 Lu 4:17,20. And so this place manifestly points to Christ, and must necessarily be understood of him, and of him only, concerning whom much is said in the books of Moses, as is evident from Luke 24:27,44 Joh 5:46 Acts 3:22, Acts 26:22 28:23. And this sense being plain, and natural, and unforced, and exactly agreeing both with the words and with the truth of the thing, and with the belief of all Christians, I see no reason why I may not acquiesce in it.