Matthew 24:36
34 I tell you the truth, this generation will not pass away until all these things take place. 35 Heaven and earth will pass away, but my words will never pass away. 36 “But as for that day and hour no one knows it—not even the angels in heaven—except the Father alone. 37 For just like the days of Noah were, so the coming of the Son of Man will be. 38 For in those days before the flood, people were eating and drinking, marrying and giving in marriage, until the day Noah entered the ark.
Sefer Chasidim 76
CommentaryWhen you see a person prophesying about the Messiah, you should know that he is either engaged in witchcraft, or has dealings with demons, or has adjured them with the Ineffable Name. Because such a sorcerer importunes the angels or the spirits, they say to him: 'Speak not in this manner, rather reveal the coming of the Messiah to the whole world.' But at the end he will be put to shame before the whole world, because he importuned the angels or the demons. And in its place misfortunes come because of him who adjured. And demons come and teach him calculations and secrets, to his shame and the shame of those who believe his words ... for no man knows about the coming of the Messiah.
Notes and References
"... The foregoing brief survey allows no more than a fleeting glimpse of the permanence, ubiquity, and power of the Messianic idea in Jewish history as manifested in unceasing calculations of the date of the Messiah's coming, and in the long string of Messianic movements centered on the person of one pseudo-Messiah after the other. As against the many rabbis and scholars who calculated the days of the advent and also the duration of the Messianic era, those who opposed such attempts were few and far in between. Let me mention here only one of them. R. Y'huda heHasid (The Pious': c. 1150-1217), principal author of the important ethical work Sefer Hasidim (Book of the Pious), went so far as to equate Messianic calculations with witchcraft ..."
Patai, Raphael The Messiah Texts: Jewish Legends of Three Thousand Years (pp. 57-58) Wayne State University Press, 1988