זוהר שמות — דף טו ע”א

The world was created by ten utterances, but three of them are the essential ones: Chokhmah-Abraham, Binah-Isaac, Daat-Jacob. When the twelve tribes were born, the world was perfected below just as it is above. The Holy One feared that Israel would intermarry with the nations, and so He sent them to Egypt where the Egyptians despised them, so that they would emerge holy. Rabbi Shimon and Rabbi Elazar sat absorbed in Torah study for two full days without eating or drinking.