Abraham had been willing to make the supreme sacrifice but God did not want it. So Israelites substituted a ram for the first born of their children. All this is the bloody background of our Lord's death. We cannot understand the meaning of it or the meaning it had for him without understanding the sacrificial context within which it occurred. Just as obviously he is going to speak Hebrew to Hebrews.
Revelation always occurs within the context of the times and in the language of the times.
God's supreme self-revelation to mankind happened in a blood sacrifice on a cross. The first Christians understood our Lord's death as a sacrifice from the beginning partly because it had occurred on the eve of the Passover when the Passover lambs were being slaughtered. And that understanding is apparent in almost every book of the New Testament. But no one theology of precisely in what sense his death was sacrificial or why it was necessary emerges in the New Testament. Preachers and theologians have been pondering the matter ever since.