The law that religion hands down as the word of Moses was in fact written far from any promised land, in bondage in Babylon, by a scribe named Ezra, under the seal of a Persian king. There are no 10 Commandments without Iraq. What comes to the people as sacred inheritance was drawn up under a foreign crown, its supplies decreed by treasurers beyond the river, its author a real man and not the mythical lawgiver whose name the books carry.
Strip the legend away and the temple and its law arrive out of Persia and Babylon, and the honest thing is to see who actually wrote it and where, rather than repeat the story that a single prophet carried it down a mountain.
River: the one universal truth that runs under many names and nations, here the boundary the Persian decree reaches across.