הדם הוא הנפש

The abode of the animal soul (nefesh habahamit), derived from the kelipat nogah in every Jew, is in the heart, in the left ventricle that is filled with blood. It is written, “For the blood is the nefesh.”

And these three aspects: action, speech and thought, they are the three general inner aspects of man that are the three aspects: soul-Neffesh, soul-Ruakh and soul-Neshama. For action, it is in the category of Neffesh, as is written (Bamidbar 15:30): “and the Neffesh that you shall make,” (Vayikra 18:29) “the Neffesh [plural] who do...” and many others, such as (Devarim 12:23) “for the blood is the Neffesh”, that the Neffesh inhabits and clothes itself in man’s blood, and therefore the crux of attributing its abode to the liver is that it is full of blood. The circulation of blood in all the parts and divisions of the limbs, the implements of action, is what provides them with vital ability and arousal, so that they will be able to enact and to perform what is in their potential. If the circulation of blood should cease from a limb, that limb will wither and won’t have the ability to do anything, and it is a dead limb.