Now Jews take blood seriously - we even speak of circumcision, Brit Milah, as a "covenant of blood." But some forms of Christianity will insist God only forgives human sin only if we participate in a “blood sacrifice.” This sounds strange to Jews, yet Christians like to point to this verse to back up this claim.
It is the blood, as life, that effects expiation (Lev. 17:11, JPS)
Let’s start with the context of this verse (verses 10-14) which is that Israelites should not eat blood when they eat animal flesh. Spilling the blood and not eating the blood of the animal you consume is an expiation for killing a living thing for food or sacrifice (bird, deer, lamb, cow) that God has created. This practice is akin to the scene in the movie Avatar where the Nabi hunter addresses the prey she's just killed and acknowledges a life has been taken and offers a ritual confession as expiation. Read it yourself:
10 And whatsoever man there be of the house of Israel, or of the strangers that sojourn among them, that eats any blood, I will set My face against that person that eats blood, and will cut him off from among his people.
11 For the life of the meat is in the blood; and I have given it to you upon the altar to make atonement for your lives; for it is the blood is in the living thing makes atonement.
12 Therefore I said unto the children of Israel: No person of you shall eat blood, neither shall any stranger that sojourns among you eat blood.
13 And whatsoever man there be of the children of Israel, or of the strangers that sojourn among them, that hunts down any beast or fowl that may be eaten, he shall pour out the blood its, and cover it with dust.
14 For as to the life of all meat, its blood is its life; therefore I said unto the children of Israel: You shall not eat the blood of any meat; for the life of all meat is its blood; whosoever eats it shall be cut off.
But setting that context aside, Christian polemics go on to argue that the death of Jesus was the perfect "blood sacrifice" that God made on our behalf. Here’s what Jews bring to this discussion:
In the Hebrew Bible, God condemns human sacrifice (Lev. 18:21; 20:2-5).
Even in the Book of Leviticus itself, blood is not necessary for the forgiveness of sins, despite what Christians may tell Jews. Even while the sacrificial system existed, a contrite poor person need only bring an offering of flour (Lev. 5:11). This teaches us that it was not the blood that was critical, it was the contrite spirit shown when someone would acknowledge his or her sin in public through any sort of sacrifice.
Throughout the Torah and the rest of the Hebrew Bible it is clear that blood is not necessary for God’s forgiveness of sins (Numbers 14:20; Lev. 5:11-13; Ezek. 18:21-28; Amos 5:21-22; Hosea 6:6, 14:2; Ps. 51:18-21; Jer. 7:22; Isa 1:11-18; Micah 6:6-8). If fact, it becomes quite clear from these verses that no sacrifices of any sort are required for God to forgive us, save the sacrifice of our own pride by admitting we’ve done wrong. Therefore…
Since the end of the sacrificial system, people’s prayers and sincere repentance are sufficient to be forgiven (see citations above).
Judaism teaches that God is demanding, but does not demand you drench your every sin in blood and death. Jewish theology assumes that God is aware He designed us to be morally vulnerable, so He knows we will make mistakes. Judaism teaches that God accommodates that reality by demanding that we repent when we do wrong. There is no blanket condemnation that requires blood and death to account for sin. When we do, God forgives us. Judaism teaches God wants better living from us, not death (SEE Ezekiel 18:23-28).