Abu Hamid al-Ghazali is a distinct figure among the mujaddids who are known as the renewers of the faith. It is clear already from the fact that he was the first to have proclaimed himself as one of them but have not been proclaimed as a mujaddid after his death. The present article emphasizes the significance of such declaration, as well as its performative (that is accepted as going beyond the simple act of speech) effect and points out its internal validity in connection with the historically developing concept and practice of tajdid. Moreover, the paper examines the interconnectedness of the milestones of al-Ghazali's life path and the stages of the epistemological “journey” he embarked on. It is shown that his rejection of certain methods of Sufism, falsafa and fiqh did not constitute for an essential abandonment of these domains, but was an attempt to return to the original core of these disciplines, as it was understood in terms of renewal and revival of religious sciences. The encyclopedic compendium compiled by al-Ghazali served the same purpose that is fulfilling the knowledge so it could serve to the one who is able to comprehend the plan of renewal. In conclusion of the article the author presents the general idea of al-Ghazali's “program” to achieve a level of knowledge in the Islamic sciences that can be tested by reason and sensory experience, with the elimination of elements unstable to such verification.