Blood is the Light of Hochma, which is the force that revives the soul and enters the fourth phase of the desire (the meat).
But it is forbidden to use the desire the Light is in. First you have to correct it separately, restrict it and make a Masach (screen), and then weigh and clarify everything. These are the laws on which the conditions of the Kasrut are later based, when meat becomes edible.
It is totally forbidden to eat the blood. In the days of the Temple they used to drain the blood into special vessels that were designated for that purpose and later were completely emptied.
Therefore, we should investigate the force that revives the soul, both in our world and in the spiritual world and thus distinguish it.
From KabTV’s “Secrets of the Eternal Book” 4/09/14