Rabbi Elazar and Rabbi Yehoshua, two of the sages who witnessed the destruction of the Second Temple in 70 CE and helped to rebuild Jewish life in the generation that followed, were once traveling together on a ship. The Mediterranean in the first century was a crossroads of the ancient world, and Rabbis often moved by sea between the Land of Israel and the Jewish communities of Egypt, Asia Minor, and Italy.
During the voyage, at a moment when the ship was gliding quietly through dark water, Rabbi Yehoshua was suddenly startled by a great light. It flashed from beneath the surface, a luminous blaze that seemed to come from something vast and alive. The veteran sage, who had seen Roman legions and wartime fires, was shaken. Rabbi Elazar, calmer, explained what it was. They were passing, he said, over the eyes of the Leviathan, the great sea-creature spoken of in Job 41 and Isaiah 27:1.
The Talmud in Bava Batra 74b and the midrashic tradition describe Leviathan as a primordial being created by the Holy One on the fifth day of creation, a creature so enormous that the world's oceans are barely its bathtub. Its scales shine, its breath is steam, and one day, in the messianic era, the flesh of Leviathan will feed the righteous at the great banquet of the World to Come. Meanwhile it swims quietly in the deeps, mostly unseen by human eyes except for rare flashes when its gaze catches the light of the upper world.
This short exemplum, preserved as number 267 in Moses Gaster's 1924 Exempla of the Rabbis, contains a whole theology in a sentence. The created world is larger than it appears. Beneath every seemingly empty stretch of water, there may be a creature whose very eye is a star. The rabbinic imagination refuses to let the ocean be merely scenery. For Rabbi Yehoshua, startled on that deck, the deep had just introduced itself.