Ps 39:8

“Because there is one will, there is one substance, there is inseparable majesty and the power of the Trinity. But there is another voice, that of the flesh; and yet, it too consents to God's will.… Christ accepted death and crucifixion so as to crucify the flesh. For my sake he took on himself the combat, so that he might conquer me. Though Christ's flesh was strong and not liable to sin, he nevertheless took on my sins. He took on my weaknesses and infirmities, though he himself was without infirmity.… He who is all pure took on our flesh to make it all pure. He, the immortal one, took on our flesh to make us immortal.”

“Let the Jews perceive that they have not prevailed against me, but that it is your will that I suffer. Besides, I desired to suffer; that is why I say in my human nature: "To do your will, O my God, is my delight." It was your will and mine that I suffer; not their plottings and power did it, but you and I desired it. You, in truth, struck your Shepherd, and the sheep have been scattered.… That I suffer was your will and mine also. What you desired, I also desired.”

“"In the head of the Book it is written of me, that I should fulfil Thy will: O my God, I am willing, and Thy Law is within my heart" [Psalm 40:8]. Behold! He turns His regards to His members. Behold! He hath Himself "fulfilled the will" of the Father. But in what "beginning of a Book" is it written of Him? Perhaps in the beginning of this Book of Psalms. For why should we seek far for it, or examine into other books for it? Behold! It is written in the beginning of this Book of Psalms! "His will is in the Law of the Lord;" that is, "`O my God, I am willing,' and `Thy Law is within my heart;'" that is the same as, "And in His Law doth he meditate day and night."”

“Next he shows his resolve to obey, according to his humanity. Now there are two things principally in a person: namely the will and the intellect. The will of a person ought to be subjected to the divine will, and the intellect ought to be directed according to the law of God. And therefore he says, "O my God," Father, insofar as God. Or, "my God," insofar as man, "I have willed to do your will," which is also my will insofar as God; or, "my God," insofar as man, "I have willed to do your will," which is also my will insofar as God. Lk. 22: "Not my will, but yours be done." Likewise, my intellect is directed according to you; hence he says, "And your law in the midst of my heart"; and he says, "in the midst," because he perfectly knows the divine reasons.”

“Head, or beginning, (Genesis i., John i., and viii. 25.; St. Jerome, &c.) or at the commencement of this book of Psalms, (St. Augustine) or rather in the whole Bible. (Calmet) — Kephalis denotes a volume, (Suidas) or stick, on which books were formerly rolled, being written on parchment. The Jews still observe the same custom in their synagogues. (Calmet) (Luke iv. 17, 20.) — Hebrew, “In the volume of the book,” means, in the book, (Amama) or the Bible, which is the book by excellence, where the incarnation and death of Christ, for man’s redemption, are clearly specified. (Haydock) — This is the sum of the Scriptures. (Worthington) — They bear witness to Christ, John v. 39., and Luke xxiv. 27. (Haydock) — The apostle uses the word capitulum, for the sum, Hebrews viii. Whatever sense be chosen, we should meditate on this head, or volume. But Christ signed, as it were, this solemn engagement, from all eternity. If we adopt the passage to David, we may translate, “I come, having on me the volume of thy Scriptures.” See 4 Kings xi. 12. (Calmet)”