Mechuyav HaMetziut (The Necessary Existent)

The Maimonidean doctrine, adopted from Avicenna's wajib al-wujud, that God is the Necessary Existent whose existence is identical with His essence and not superadded to it, while everything else is possible-in-itself and necessary only through its cause. Load-bearing in the Guide's proof of God from necessity and contingency (II:1, the Third Speculation, resting on Premises 19-21) and in the derivation of divine incorporeality and simplicity. Distinct from the Kabbalistic Ein Sof (a later, independent apophatic development) and from the attribute-negation doctrine (shelilat ha-to'arim / negative-theology), though Guide I:57 fuses the two.