Why God Appears as Warrior, Scribe, Youth, and Elder

Midrash Tanchuma Buber, Yitro 16:2

Another interpretation: Because the Holy One, blessed be He, appeared to them at the sea as a warrior waging war, and appeared to them at Sinai as a scribe teaching Torah, appeared to them in the days of Solomon as a young man, and appeared to them in the days of Daniel as an elder, the Holy One, blessed be He, said to them: It is not because they see Him in many forms [that there is more than one God]. I am He who was at the sea; I am He who was at Sinai. "I am the LORD your God."

Themes

Biblical References