Singing the old Psalm...

Consequently, when Christ came into the world, he said,
“Sacrifices and offerings you have not desired,
but a body have you prepared for me;
in burnt offerings and sin offerings
you have taken no pleasure.
Then I said, ‘Behold, I have come to do your will, O God,
as it is written of me in the scroll of the book.’”
(Hebrews 10:5-7 ESV)
As the writer of this letter was prone to do, he quotes from a Psalm of David, which looked forward to the coming of the Messiah.  David, the man after God's own heart, understood His heart.  He does not want rituals or sacrifices, but a life of wanting to please Him.  The Christ lived that life. He came to give the Father both: the life that pleases Him, and the death to pay for our sins.  After saying more about this priestly work of Christ, he implores us to come to God through Him, and to find a confident relationship with Him, where we want to obey Him, we want to please Him, and it is our joy to do so.  Christ is the one we long for in the old psalm, Psalm 40.