MOSES AT THE BURNING BUSH THE fifth descent was when He came down to the thorn-bush, as it is said, "And I am come down || to deliver them out of the hand of the Egyptians" (Ex. 3:8). He abandoned the entire mountain, and descended into the thorn-bush, and He abode therein. And the thorn-bush was (an emblem of) grief and distress, and it was full of thorns and thistles. Why did He abide in the midst of the thorn-bush which was (an emblem of) grief and distress? Because He saw Israel in great grief and He also dwelt with them, thus fulfilling that which is said, "In all their affliction He was afflicted" (Isa. 63:9).
Rod and Serpent of Shekhinah
Pirkei DeRabbi Eliezer 40:1