“Yet the only text in St. Paul which directly applies sacrificial phraseology to the death of Christ is that of the Epistle to the Ephesians:
He gave himself up for you as an offering and a sacrifice (prosphoran kai thusian) to God, as a fragrant perfume.
It seems undeniable that, in expressing himself in this way, St. Paul was thinking of the text of Psalm 39.7-9.
You took pleasure neither in sacrifice nor in offering,
but you have opened my ears:
You have desired neither holocaust nor sacrifice for sin;
then I said: “Here am I, I am coming,
in the scroll of the book I am spoken of.
My God, I have delighted in doing your will
your law is in the depths of my heart…
In other words, what the psalmist presents as something other than ‘sacrifice and offering’ and as what God prefers to them, is now described by the very terminology proper to what this has replaced. This transfer is extremely important. It is found at the basis of the whole sacrificial vision of the Epistle to the Hebrews, even though too many commentators have neglected to note this fact.
We might be tempted to link up, with this unique text of St. Paul’s on the death of Christ as a sacrifice, another text found in the Epistle to the Romans. For the latter seems at first sight to lead directly into the sacrificial and, precisely, expiatory developments in the Epistle to the Hebrews:
We are freely justified by his grace, by the redemption which is in Christ Jesus, whom God has predestined to be a propitiation by faith in his blood.
This text certainly brings us close to the Epistle to the Hebrews with this mention of propitiation, but we should note that here the implicit image of sacrifice is not applied directly to Christ’s death but rather to our faith in that death. Here, as elsewhere, the notion by which St. Paul explains the Cross is not that of sacrifice, but of redemption, that is, ransoming of slaves.”
(Louis Bouyer, The Spirituality of the New Testament and the Fathers, p. 142-143)