Central to Nation of Islam theology is the doctrine that Wallace Fard Muhammad, who appeared in Detroit's Black community in 1930 selling goods door to door before establishing the movement's first temple, was not a prophet or a reformer but God in person, a teaching Elijah Muhammad stated plainly and that distinguishes Nation of Islam belief sharply from the classical Islamic doctrine of tawhid, which holds God as radically transcendent, without body or physical location, and never incarnate in any human being, a point on which mainstream Muslim theology across every major school agrees despite their many other disagreements. C. Eric Lincoln's fieldwork based study describes how this identification of Fard as God incarnate functions as the theological foundation beneath the movement's other distinctive teachings, since if Fard himself is divine, then Elijah Muhammad's status as his chosen Messenger carries an authority Nation of Islam theology treats as directly divine instruction rather than as one more human interpretation among many competing readings of scripture. Fard himself left few personal records and disappeared from public life around 1934, so what is known of the doctrine comes almost entirely through Elijah Muhammad's own teaching about him rather than through any surviving statement in Fard's own words.