With chapter 17, there is a change in the book of Leviticus. Though “holiness” and the call to be holy has been seen before this, the whole idea of the “separateness” of God’s people becomes more pronounced beginning here. Chapter 17 forbids worship of God in any other way and in any other place other than that prescribed specifically by the Lord. To sacrifice an animal to another god, or to sacrifice in another way or place is to make the offerer guilty of a wanton disregard for life – in this case, animal life. The penalty was to be cut off from the people of God. To act like a non-Israelite was to make one, in effect, a non-Israelite.
All life is special to God and this fact was emphasized in the prohibition against drinking blood. God decreed that life was in the blood and life, all life, belongs to him. It was not to be consumed as food, but rather poured out on the ground – returned to the Lord.
In view of the prohibition against drinking blood, you can understand why, when Jesus said “unless you eat my flesh and drink my blood you have no life in you” (John 6) many of his followers stopped being disciples. It was a call to violate the specific teachings of the Law.
But there is a difference.
Israel was prohibited from drinking the blood of a life “taken,” not from consuming a life “given.” By partaking of Christ’s life, given by him to be consumed, the Christian makes himself one with Jesus and thus, partakes of Christ’s eternal life. The weekly Lord’s Supper is a symbolic re-enactment of what ought to be more than symbolic in our lives.