18 Therefore not even the first covenant was dedicated without blood. 19 For when Moses had spoken every precept to all the people according to the law, he took the blood of calves and goats, with water, scarlet wool, and hyssop, and sprinkled both the book itself and all the people,
Verses 18–22 show that the Mosaic Covenant was effected by a blood ceremony (Ex 24). These verses provide an example from Exodus to show the need of blood sacrifice for forgiveness. The principle of these verses is that forgiveness demands blood sacrifice.
The “therefore” here shifts to a new but related subject. This word moves the reader from the general principle to a specific deduction by example from Exodus.
not even the first covenant [Mosaic] was dedicated [put into effect] without blood.
The Mosaic Covenant was put into effect by blood. The Old Testament law formally began on the inauguration of blood sacrifice.
The word “for” confirms Hebrews 9:16 and gives the grounds for the previous verse. Verses 19–21 summarize the ratification of the covenant by a ceremony (Ex 24:1-8).
when Moses had spoken every precept to all the people according to the law,
The reference here is to Exodus 24. After reading the terms of the covenant, Moses sprinkled the altar and people with blood.
“All” or “every” are used five times in verses 19–22, stressing the necessity of cleansing by blood. “Every precept” refers to Exodus 20:22.
he took the blood of calves and goats, with water, scarlet wool, and hyssop, and sprinkled both the book itself and all the people,
The purpose of sprinkling of blood was for purification.
Christ’s death is the only means of salvation.
The Old Covenant was activated by the death of animals and the New Covenant was activated by the death of Christ. Old Testament sacrifices were not the means of salvation but symbols of the ultimate sacrifice in Christ. They were, however, examples of death to ratify a promise.