The aim of this paper is to identify the position the ru'yat Allāh holds within the curriculum of sciences described by the Iḫwān al-Ṣafa'. Their concept of knowledge is first clarified. The Ihwan use the terminology of rational knowledge to describe items of faith too. But faith is only an introduction to a greater knowledge. Now: is the supreme knowledge to be considered as speculative and theoretical, or are the ḫawciṣṣ, the only ones entitled to the vision of God, eventually obliged to rely on a kind of divine “revelation” or “inspiration”? If the “vision of God” appears beyond any possible connotation of knowledge in “rational” terms, it is unclear, however, whether the Ihwan use the concepts of “revelation” and “inspiration” as a way of explaining in a theological terminology the utmost degree of human knowledge (perhaps according to the same analogical function waḥy and ilhām appear to have in Ibn Sīnā). Moreover, the qualities and moral dispositions attributed to the “Friends of God” remind us of Sufi doctrines. Consequently, the question of the relation between Sufism and imāmite theories could be re-opened: the Iḫwānian definition of the “science of the transcendent” shows that the gnoseological itinerary is not concluded even with the “vision of God.”