The motif of the blood is so strong, so central, and so important in the Pentateuch that it's impossible to separate it from the motif of sacrifice and atonement for sins, which are interrelated.
The Pentateuch teaches that when someone sins, they must be put to death, or that someone or something else needs to take their place and die in their stead. But now, since there is no Temple, no sacrifices, and no priests, more and more modern rabbis refuse to recognize the importance and centrality of blood for the atonement and forgiveness of sins. The radicals among them exaggerate and take it even farther. See the sayings of Rabbi Daniel Asor for example:“Christianity’s obsession on the subject of ‘atonement for sins' through someone else’s pure blood, comes from the Pagan idolatry of ancient religions.” Rabbi Asor found a creative way to avoid dealing with God’s demand in the Pentateuch, for a blood sacrifice as atonement for sins, by claiming that this is paganism and idolatry. If this is true, why did God demand it from the people of Israel in such a clear way?

Blood Atonement in the Bible

On the eve of the Exodus from Egypt, it was the blood of an innocent Passover lamb, that was smeared on the doorposts and lintels that served as a sign for the angel of death. As it is written in Exodus 12:13: “The blood shall be a sign for you, on the houses where you are. And when I see the blood, I will pass over you, and no plague will befall you to destroy you, when I strike the land of Egypt.”
In Exodus 24, when God made the covenant on Mt. Sinai with the People of Israel, the People of Israel went through purification by blood, and God’s covenant with the People was made with blood: “And Moses took half of the blood and put it in basins, and half of the blood he threw against the altar. Then he took the Book of the Covenant and read it in the hearing of the people. And they said, ‘All that the LORD has spoken we will do, and we will be obedient.’ And Moses took the blood and threw it on the people and said, ‘Behold the blood of the covenant that the LORD has made with you in accordance with all these words.’” (Ex. 24:6-8)
Onkelos translation, the most important translation of the Pentateuch to Aramaic, which was used in the synagogues during the first centuries after Jesus, included the word “atonement” to Exodus 24:8: “And Moses took the blood and threw it on the altar for atonement for the People.”
In Exodus 30, the Day of Atonement is mentioned for the very first time in the Pentateuch: “Aaron shall make atonement on its horns once a year. With the blood of the sin offering of atonement he shall make atonement for it once in the year throughout your generations. It is most holy to the LORD.” (Ex. 30:10)

Did you notice? This verse, which mentions the Day of Atonement for the first time, doesn’t mention anything in regards to prayer, to good deeds, to fasting or to charity. There is no doubt that these things are important and essential, but the Pentateuch only speaks about blood. Why? Because the atonement ceremonies, are strongly linked to blood. If we take away the blood, there is no sacrifice, no atonement, no forgiveness of sins.

Jewish Sages Acknowledged the Importance of Blood for Atonement

In Leviticus 16, God explains to Moses how the sins of the People of Israel will be forgiven, by taking the blood which was offered at the altar, and sprinkling it on the Mercy Seat as atonement for the iniquities and sins of the People of Israel. Even the Sages recognized this.
Yalkut Shimoni says on Exodus 29: “There is no atonement but in the blood.”
In tractate Yoma 5a it says: “And he shall lay his hand… and it shall be accepted for him. Does the laying on of the hand make atonement for one? Does not atonement come through the blood?”
Rashi himself said: “There is no atonement without blood.”
The Sages also recognized this principle and repeated it in Zevachim 6; Minchot 93; Sifra 4, and more. And yet, Rabbi Asor calls what God defined in the Pentateuch as the only way to receive atonement and forgiveness over sins as paganism and idolatry.

Why is Blood Sacrifice Essential?

The Book of Leviticus, the book which is dedicated in detail to the sacrifices and atonement for sins, talks about atonement 49 times! Each time, the context is always the blood sacrifices. Why blood is so important to God?
In Leviticus 17:10, God commands not to eat blood, and in the next verse, He explains why the blood is so important: “For the life of the flesh is in the blood, and I have given it for you on the altar to make atonement for your souls, for it is the blood that makes atonement by the life.” (Lev. 17:11)
According to Leviticus 5, even the poor, who had no money to buy an animal and sacrifice it, needed to bring fine flour to the high priest, and what did the high priest absorb the flour in? In the blood on the altar, and then sacrificed it. So what will happen if a rabbi comes and claims that the blood sacrifice is only one of the ways for forgiveness of sins, but not the only way?
Let’s quote again the words of Rabbi Asor: “There are various methods to obtain forgiveness of sins, like repentance, prayer and charity… Sacrifice offerings is the less preferred way.” Rabbi Asor contradicts himself, as he claimed at first that this is a pagan idolatry custom, but now, he is compromising by saying that it is possible to obtain forgiveness of sins through the offering of a sacrifice but that God is not really interested in that. The answer to this is simple, this is a modern excuse in order to hide the need for Jesus from us, the Messiah who's blood was shed as a sacrifice for our sins.

The Jewish researcher, Professor Geza Vermes wrote: “According to Jewish theology, there can be no expiation without the shedding of blood.”

Also Professor Bruch Levin, in his commentary on Leviticus wrote: “Expiation by means of sacrificial blood-rites is a prerequisite for securing God’s forgiveness. As the rabbis expressed it, there is no ritual expiation except by means of blood.”
To conclude, Rabbi Asor and those like him, will prefer to contradict the Sages and even the Law of Moses, only so they won’t have to deal with God’s demand of blood for forgiveness of sins, and with the fact that Jesus the Messiah, He is the One who provided for this need. Jesus is not only the Priest who offers a sacrifice for us, but He in Himself, is the High Priest, who shed His blood as a sacrifice for our sins, once and for all.