The covenant made on Sinai was also in the form of a will which was put into effect by a death. The writer proves this from the fact that it too was not dedicated without blood.
We remember that curtain separating the holy of holies from the main sanctuary of the temple and the un-approachability of God, his blazing, dazzling holiness, and our sinfulness. Death needed to take place, and blood needed to be shed in order to secure access. There is a penalty to pay, and that is taught in the sacrifices of the old covenant; the wrath of God has to be appeased. Some people don't like this language. The wrath of God? Yes, the blazing holiness of God, his indignation and his righteous indignation against sin and rebellion, the horrible things that dwell in the human heart. The righteous indignation of a holy God has to be expressed and the sin has to be punished. I have stolen my life from God and my years; I have eaten his food and breathed his air. I have taken the things that are his, my gifts and powers, and spent them all on myself. What a debt I owe to God, and the debt has to be paid. The offence has to be purged, and it can only be done by death. Christ has come to bear that punishment for us; there has to be suffering. This is so solemn: the holiness of God is involved.
Why is it that the English word chosen to signify the two major divisions of the Bible is ‘testament’ – Old Testament and New Testament? In the KJV the Greek word is rendered ‘covenant’ 20 times, and ‘testament’ 14 times., but if the two parts had been called the Old Covenant and the New Covenant, the terminology would have been confusing because the Jewish portion of Scripture contains more than one covenant. The word ‘testament’ appropriately identifies the two most significant covenants, and only these two took the form of a testament. The term ‘new testament’ is found in Hebrews 9:15 where the context requires this translation, and the versions which use the words ‘new covenant’ in this place, make the meaning more obscure. Both of the English words ‘covenant’ and ‘testament’ are derived from Latin, but the two divisions became known as the Vetus and Novum Testamentum in the Latin church, and this has found its way into English.