In the last chapter (Chapter 1000th) of his monumental book Mishne Tora, Maimonides conveys a very interesting idea about the Messianic times, which sheds light on the limits and credibility of Jewish oral tradition.
First (MT, Melakhim 12:1) Maimonides asserts that nature will not change in Messianic times. He also says (12:2) that apparently, it will be a war between Gog and Magog and before that a Prophet will come to guide the Jewish people in the right path and to establish peace on earth.
Then he explains: vekhol elu hadebarim.... "in all these matters [related to the messianic age] and similar to them [=events which will happen in the future], no man will be able to know how will they happen until they actually happen. Because although the Prophets wrote [metaphorically] about these matters, the meaningof what they said is unknown to us [debarim setumim] because our Rabbis do not have any tradition [kabbala = oral tradition] as to how these words should be understood. And that is why the Rabbis have different opinions on these matters. In any case, the order in which these events will occur or their details, are not a foundation of our faith. [And since there is no tradition on these matters, and the Rabbis just speculated about the interpretation of the words of the Prophets] a person should therefore not involve himself in analyzing the Hagadot [=Rabbis parables] and Midrashim [=Rabbis interpretations] on these matters, because learning these subjects will not bring a person to love God or to fear God. One should likewise refrain himself from calculatingwhen the Mashiaḥ will come. Our sages have warned us about this negative practice by saying: 'May the souls of those who calculate the coming of the Mashiaḥ be rot'. One must hope and believe in general that the Mashiaḥ will come, as we have explained".
All about the Mashiaḥ by Aryeh Kaplan z"l, from Aish.com