Exodus 34:29-30

Now it happened, when Moses came down from Mount Sinai with the two tablets of the Testimony in his hand when he came down from the mountain, that Moses did not know that the skin of his face was radiant, because God had spoken with him. When Aaron and all Bnei-Yisrael saw Moses, the skin of his face shone in rays, so they were afraid to come near him.