Blood is required for atonement (Leviticus 17: 11)

Life is in the blood, and I have given you the blood of animals to sacrifice in place of your own.

Chapter 17 of Leviticus has concentration on the holiness of God. The reason forgiveness of sins is necessary is because God desires to dwell with those who are holy. God makes a special point of insisting that life is in the blood. Previously we learned that the scape goat was a sin bearer for the transgressions of Israel corporately. Now we learn on a individual level the shedding of blood of the sacrifices is the atonement for the individual's trespasses. Hence book has atonement value: the blood shed by the offer, who thereby was cleansed of his sin.
From the New Testament we learn that the Jews kept up this practice - even Jews who has become Christians. Some Jews, indded, were scandalized by the fact that Christians of Gentile background did eat blood, so the Counsil at Jerusalem (Acts 15) laid down a prohibitation against it.

Daily Prayer: Lord, in my day I realize that we are no longer under the Law as in earlier days. Our only law now is to love you with all our strength and our mind and to love our neighbor as ourself against which there is no law. In Jesus name I pray Amen.