Kelippot (Kabbalah)

See section 83, where it is explained that spiritual beings are separated and divided from one another by their difference of form. Know that divergent forms, from one extreme to the other, separates these beings and distances them from one extreme to its opposite, until there is no suckling between them at all. As you already know, the supernal light contains only a will to give, not to receive anything, whereas the kelippot have the exact opposite forms: Only a will to receive and to swallow everything; they have no will to give whatsoever. Therefore, they are separated from the Source of Life and are called dead, they and all that cleave to them. This must be understood (Talmud Eser Sefirot, v. 3, Q & A 88).