Along with the laws governing which animals can and cannot be eaten and how they have to be ritually slaughtered, the Torah commands us to not eat the blood of animals. In fact, the Torah repeats this many times in order to emphasize the importance of not ingesting blood. The reason given is that the “soul of the animal is in the blood.”
Until the flood at the time of Noah man did not eat animals. Only after the flood, as a concession to man’s lower spiritual level, did the Torah allow eating flesh. Although the Torah permits Jews to eat meat it does so only in a very prescribed manner. Since it repeats not only the commandment not to eat the blood, but the reason as well, this tells us the importance of this commandment. Drinking blood was used extensively in many different idol worship and pagan rituals. This is actually true to this day. Drinking the blood of an animal was thought to give the person the spirit and the characteristics of the animal, which is exactly why the Torah forbids it. We are what we eat and although the Torah permits eating meat it is only if the essential soul of the animal contained in the blood is not eaten.
We all have both an animal and Divine soul which accounts for so much of the inner struggle we all experience on a daily level. Each has its purpose, but in general the animal soul must be carefully controlled and taught how to act in a holy manner. This is the reason behind many of the commandments and especially the prohibition of eating blood which strengthens the animal soul immeasurably, to the detriment of the Divine soul, which for a Jew must be dominant.