It is well known that Islam is the religion of tawhid–unity (to unify, to believe in the oneness of Allah). The statement that summarizes the religion of Islam, Lā ilāha illā Allāh Muḥammadun Rasūl Allāh (There is no deity but Allah, Muhammad is the Messenger of Allah, peace be upon him), is also recognized as the "tawhid phrase" (kalimat al-tawhid).
Tawhid is also a term in Sufism (taṣawwuf). According to the classifications of some Sufis such as ʿAbd Allāh al-Harawī, it is the final maqām (spiritual station). That is, the one who completes the Sufi training reaches the maqām of tawhid and becomes the perfect human (al-insān al-kāmil).
The phrase "There is no deity but Allah" has, by some Sufis, been transformed in the context of existence into "There is no existence but Allah" (lā mawjūda illā Allāh). The name of this system is waḥdat al-wujūd (the unity of being).