The specific sense that the word xratu- possesses in the Gāthās has not received the attention it deserves. As this article will show, this specific sense points to the eschatological foundation of Zoroastrianism. Eschatological concerns did not first develop in the frame of an established “monotheistic” religion; rather, Zoroastrianism arose from those concerns. The xratu- has a strictly eschatological function in the Gāthās. The noun retains this semantic capacity not only in the Young Avestan but also in the Middle Persian Zoroastrian texts. Iranian languages share the noun with Vedic and (archaic) Greek, where it has the basic meaning of the mental capacity to achieve proposed goals, hence practical intelligence, resourcefulness, or efficacy. If this is in fact the general sense that xratu- has in Iranian, as will be briefly pointed out, the specifically eschatological meaning that it acquires in the Gāthās must indicate the type of religious discourse to which these compositions belong. The noun may, further, have developed its eschatological meaning before the time of the Gāthās and already become a technical term. In this case, it would be legitimate to ask whether there are traces in the Gāthās that point to the institutional background of the term. There do indeed seem to be such traces. The term seems to have been used in the technical sense of the mental power to attain the divine sphere in the daēva cult.