Hebrews 10:5-7 meaning

The Pauline Author quotes Psalm 40:6-8, framing it in a such a way to make Jesus the speaker of the psalm. In the psalm, Jesus is talking to God, saying that God does not truly care about animal sacrifices, that He takes no pleasure in them, emphasizing once again that these sacrifices were just symbols of what was to come:

Therefore, when He comes into the world, He says, "Sacrifice and offering You have not desired, but a body You have prepared for Me; in whole burnt offerings and sacrifices for sin You have taken no pleasure. "Then I said, 'Behold, I have come (in the scroll of the book it is written of Me) to do Your will, O God.'" (vv 5-7)

The mentioning of whole burnt offerings here refers to the sacrifices described in Leviticus 1. The Hebrew word for burnt offerings in the Bible is "Oleh" which means "ascent". The ancient Israelites called burnt offerings "offerings of ascent" in their language due to the image of the offering ascending to God from the altar in the smoke. Jesus fulfilled this offering being a human offering who ascended to His Father (Acts 1:9).

Jesus, instead, has a human body prepared for Him by God and has come to the earth (as prophesied) to do God's will. It's true that God required animal sacrifices from the Israelites. The requirement wasn't for His delight or appeasement, it served a different purpose, to remind the Israelites of their sin, God's holiness and to provide a way for sinners to be reconciled to God and each other, but those sacrifices could never truly deal with the sinful nature passed from Adam to every human (Hebrews 10:1).

In the Levitical system instituted by Moses after the exodus from Egypt, substitutionary atonement is a core theme. An innocent animal's blood must be shed on behalf of the offeror. The offeror would place their hands on the head of the animal sacrifice symbolically transferring their identity and sins onto the innocent animal (Leviticus 4:4). These offerings were practiced for thousands of years and ultimately point to Christ's work on the cross, taking our place, the life of the innocent on behalf of the guilty.

Even with the sacrificial requirements under the Levitical system, many people of God in the Old Testament could see that God was more interested in obedience from the heart than these continual offerings. The prophet Samuel confirms this when rebuking King Saul:

"Samuel said, "Has the LORD as much delight in burnt offerings and sacrifices as in obeying the voice of the LORD?
Behold, to obey is better than sacrifice,
And to heed than the fat of rams."
(1 Samuel 15:22)

God instituted animal sacrifice both as a symbol and as an act of service intended to shape the heart. But the sacrifices were not sufficient of themselves. When Jesus died for our sins He was both fully obedient as well as the sacrifice for our atonement.

It is fascinating to reflect upon the words Jesus spoke as He entered the world. At Christmas, when we celebrate the Nativity, we tend to focus on what was said in the world around Jesus at His birth. But these are the words and thoughts of Jesus Himself as He stepped forward in time to take on the form of a human and be born as a babe in a manger.

Jesus willfully and knowingly left His place in heaven and took on the form of a human in order to obey His Father's will. Philippians exhorts us to adopt the same mindset as Jesus did, not regarding His status in heaven as something to be grasped, but rather emptied Himself and became a servant (Philippians 2:5-8). As a result of His obedience, the Father has exalted Jesus above all (Philippians 2:9-10).