The use of the crystallized third-person singular forms of the verb δέω is fairly consistent throughout Greek literature, both in syntactic construction and in semantic value. It conveys meanings such as "it is necessary," "one must," or "it is fitting". In the majority of attestations from the Hellenistic and Roman periods, δεῖ appears primarily to refer to logical or epistemic necessity. Furthermore it designates ethical and religious obligations arising from systems of civic, moral, and cultic law. Contrary to what might be expected from the wide range of nuances found in other Greek literature, the Septuagint employs δεῖ only sporadically and with a rather stable semantic value. In fact, the verb here tends to assume a meaning closely connected with legislative practice and, even more frequently, with social customs. Only rarely does it refer to the divine will. At times a moral or religious nuance may be perceived, yet any reference to predestination or providential necessity - attested in certain occurrences within Greek literature - appears to be absent. This tendency is completely reversed in the Book of Daniel. Here, in most occurrences, the use of δεῖ becomes fixed in the formula ἅ δεῖ γενέσθαι, which carries a distinctly eschatological sense. This meaning will come to prevail in the Apocalypse and in the Gospels. In the latter it is also accompanied by a notion of predestination that is embodied in the figure of Jesus and in his fulfillment of scriptural prophecies. This paper seeks to demonstrate this pattern through the discussion of several significant passages.