זוהר בראשית — דף עה ע”ב

Rabbi Shimon explains that the gate is closed during the six working days and opened on the Sabbath and on the New Moon: on weekdays the powers rule the world except the Land of Israel, while on the Sabbath and New Moon the gate is open and the moon joins the sun. Rabbi Isaac asks what the builders of the tower saw, and Rabbi Shimon answers that they traveled from the Land of Israel to Babylon and thought they had found a place to cling and to nourish the world. The Lord confounded their language, since the host above recognizes only the holy tongue; their strength weakened and they stopped building. The text adds that the Holy One, blessed be He, brought the secrets of wisdom down into the world, and that He had given it to the first man.