Hebrews 10:5

Heb. 10:5. Wherefore, when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me;

Blank Bible: "[Body hast thou prepared me] see Bp. Kidder's Dem. Part 2.89-92 and Owen in Loc. p. 28.p.b.c.d.e."

One may wonder how this text has anything to do with freedom of the will, but Edwards sees profound relevance:

9. That it should be possible for Christ to fail of doing his Father's will, is inconsistent with the promise made to the Father by the Son, by the Logos that was with the Father from the beginning, before he took the human nature: as may be seen in Psalms 40:6-8 (compared with the Apostle's interpretation, Hebrews 10:5-9), "Sacrifice and offering thou didst not desire: mine ears hast thou opened (or bored); burnt-offering and sin-offering thou hast not required. Then said I, Lo, I come: in the Volume of the Book it is written of me, I delight to do thy will, O my God, and thy law is within my heart." Where is a manifest allusion to the covenant which the willing servant, who loved his master's service, made with his master, to be his servant forever, on the day wherein he had his ear bored; which covenant was probably inserted in the public records, called the "Volume of the Book," by the judges, who were called to take cognizance of the transaction (Ex.. 21). If the Logos, who was with the Father, before the world, and who made the world, thus engaged in covenant to do the will of the Father in the human nature, and the promise, was as it were recorded, that it might be made sure, doubtless it was impossible that it should fail; and so it was impossible that Christ should fail of doing the will of the Father in the human nature.

Heb. 10:6