The canonical books of Judaism, to which we turn for the definition of theological categories and doctrines, rarely set forth ideas in the form of abstractions and generalizations, with the result that understanding any generative theological categories requires the philological exegesis of texts. In the case of the Judaic canon, the pertinent texts are those of the Torah, written and oral. When we turn to the written Torah, which the West knows as the Old Testament, and to the Oral Torah, which Judaism assembles out of the Mishnah, the two Talmuds, the Midrash-compilations of the formative age, our work only begins. For we have also to determine for ourselves what words, in the canonical writings, stand for, or refer us to, the counterpart category that our Christian and Greek philosophical heritage has conferred upon us. When, as we shall see, we ask ourselves about how the classical theology of Judaism conceives of ‘eternity’, we therefore engage in a prior inquiry into what we mean by ‘eternity’ and how in the Judaic canon's substrate of theology we may locate the counterpart-language for that meaning. Not only so, but we have further to find out in what context thought takes place on the category, ‘eternity’: when and why is discourse on eternity precipitated in the canonical theology of Judaism? And when not?