[Pooya/Ali Commentary 2:163] There is no god but Allah. There is only One God, and all attributes belong to Him. His main attribute is an all-encompassing beneficence and mercy. The "unity of God" is the main and single fundamental upon which the whole structure of the religion of Islam rests, through which all guidance and enlightenment emerge. Aqa Mahdi Puya says: The word wahid (one) is not used in any numerical sense, nor in the sense of order (the first of any second), nor in the sense of the oneness of a genus or a specie, nor in any other general term, but it is used in the sense that He is indivisible, unanalysable organically, chemically, geometrically, logically, mentally or physically, or in any sense whatsoever. This unity, in essence, does not correspond to any limitation. Since He is unlimited, a second, an equal, or an opposite to Him is not conceivable. Ibna Babwah writes in the book of Tawhid: In the battle of Jamal a Bedouin asked Ali: "Do you say that God is One?" Some companions did not like the idea of asking such a question at a time when Ali was fighting a war, and they rebuked him. But Ali ibna abi Talib said: "Do not disapprove his question, because what he asks is the very object of this battle. We are demanding the true answer to this question (same faith in the unity of Allah) from our enemy." Then Ali gave the above-noted description of Tawhid.