Albert Barnes Commentary Hebrews 10:7

"Then said I, Lo, I am come (In the roll of the book it is written of me) To do thy will, O God." — Hebrews 10:7 (ASV)

Then said I. I the Messiah. Paul applies this directly to Christ, showing that he regarded the passage in the Psalm as referring to him as the speaker. Lo, I come. Come into the world (Hebrews 10:6). It is not easy to see how this could be applied to David in any circumstance of his life. There was no situation in which he could say that, since sacrifices and offerings were not what was demanded, he came to do the will of God instead of them.

The time here referred to by the word "then" is when it was clear that sacrifices and offerings for sin would not achieve all the desired purposes, or when, in view of that fact, the Redeemer's purpose is understood as being formed to begin a work that would accomplish what they could not.

In the volume of the book it is written of me. The word here translated "volume"—kefaliv—means, properly, a little head, and then a knob. Here it refers, undoubtedly, to the head or knob of the rod on which the Hebrew manuscripts were rolled. Books were usually written so as to be rolled up; and when they were read, they were unrolled at one end of the manuscript and rolled up at the other as fast as they were read. (See Barnes on Luke 4:17).

The rods on which they were rolled had small heads, either for the purpose of holding them or for ornament. Hence, the name head came metaphorically to be given to the roll or volume.

But what volume is intended here? And where is that written which is referred to here? If David was the author of the Psalm from which this is quoted (Psalms 40), then the book or volume that was then in existence must have been principally, if not entirely, the five books of Moses, and perhaps the books of Job, Joshua, and Judges, with probably a few of the Psalms.

It is most natural to understand this of the Pentateuch, or the five books of Moses, as the word "volume," at that time, would undoubtedly have most naturally suggested that. But plainly, this could not refer to David himself, for in what part of the law of Moses, or in any of the volumes then existing, can a reference of this kind be found to David?

There is no promise, no intimation that he would come "to do the will of God" with a view to accomplish that which could not be done by the sacrifices prescribed by the Jewish law. The reference of the language, therefore, must be to the Messiah—to some place where it is represented that he would come to accomplish by his obedience what could not be done by the sacrifices and offerings under the law.

But still, in the books of Moses, this language is not literally found. The meaning must be that this was the language which was implied there respecting the Messiah, or this was the substance of the description given of him: that he would come to take the place of those sacrifices, and by his obedience to death would accomplish what they could not do.

They had a reference to him. It was contemplated in their appointment that their inadequacy would be such that a need for a higher sacrifice would be felt, and when he would come, they would all be abolished. The whole language of the institution of sacrifices, and of the Mosaic economy, was that a Savior would afterward come to do the will of God in making an atonement for the sin of the world.

That there are places in the books of Moses which refer to the Savior is expressly affirmed by Christ himself (John 5:46) and by the apostles . That the general spirit of the institutions of Moses had reference to him is abundantly demonstrated in this epistle. The meaning here is, “I come to do thy will in making an atonement, for no other offering would expiate sin. That I would do this is the language of the Scriptures which predict my coming, and of the whole spirit and design of the ancient dispensation.”

To do thy will, God. This expresses the sum of all that the Redeemer came to do. He came to do the will of God:

1. By perfect obedience to His law; and
2. By making an atonement for sin—becoming obedient unto death (Philippians 2:8).

The latter is the principal thought here, for the apostle is showing that sacrifice and offering such as were made under the law would not put away sin, and that Christ came, in contrast to them, to make a sacrifice that would be efficacious.

Everywhere in the Scriptures it is presented as being the "will of God" that such an atonement should be made. There was salvation in no other way, nor was it possible that the race should be saved unless the Redeemer drank that cup of bitter sorrows .

We are not to suppose, however, that it was by mere arbitrary will that those sufferings were demanded. There were good reasons for all that the Savior was to endure, though those reasons are not all made known to us.