Psalms 40:7 - Clarke's commentary and critical notes on the Bible

Then said I, Lo, I come: in the volume of the book it is written of me, In the volume of the book - במגלת ספר bimegillath sepher, "in the roll of the book." Anciently, books were written on skins, and rolled up. Among the Romans, these were called volumina, from volvo, I roll; and the Pentateuch in the Jewish synagogues is still written in this way. There are two wooden rollers; on one they roll on, on the other they roll off, as they proceed in reading. One now lying before me, written on vellum, is two feet two inches in breadth and one hundred and two feet long. To roll and unroll such a MS. was no easy task, and to be managed must lie flat on a table. This contains the Pentateuch only, and is without points, or any other Masoretic distinction. The book mentioned here must be the Pentateuch, or five books of Moses; for, in David's time no other part of Divine revelation had been committed to writing. This whole book speaks about Christ, and his accomplishing the will of God, not only in "the seed of the woman shall bruise the head of the serpent," and "in thy seed shall all the nations of the earth be blessed;" but in all the sacrifices and sacrificial rites mentioned in the law.