וְעַתָּ֗ה מַה־לָּךְ֙ לְדֶ֣רֶךְ מִצְרַ֔יִם לִשְׁתּ֖וֹת מֵ֣י שִׁח֑וֹר וּמַה־לָּךְ֙ לְדֶ֣רֶךְ אַשּׁ֔וּר לִשְׁתּ֖וֹת מֵ֥י נָהָֽר׃
And now what hast thou to do in the way to Egypt, to drink the waters of Shihor? Or what hast thou to do in the way to Assyria, to drink the waters of the River?
Read Jewish philosophy on Jeremiah 2:18: Rambam's Guide for the Perplexed, Saadia Gaon, and classical Jewish philosophical sources, free online.