Tawhid, also spelled Tauhid, Arabic Tawḥīd, (“making one,” “asserting oneness”), in Islam, the oneness of God, in the sense that he is one and there is no god but He, as stated in the shahādah (“witness”) formula: “There is no god but Allah and Muhammad is His prophet and Messenger.

” Tawhid further refers to the nature of Allah—that He is  unique, not composed, not made up of parts, but simple and uncompounded and  not comparable to anything.

The doctrine of the unity of Allah and the issues that it raises, such as the question of the relation between the essence and the attributes of Allah, reappear throughout most of Islamic history. In the terminology of Muslim mystics (Sufis), however, tawhid has a monotheistic sense; all essences are from Allah, and there is no absolute existence besides that of Allah.

To Muslim scholars, the science of tawhid is the systematic theology through which an absolute knowledge of Allah may be reached, but, to the Sufis, knowledge of Allah can be reached only through religious experience and direct vision.

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