Exodus 34:27-29

Then the LORD said to Moses, “Write down these words, for in accordance with these words I have made a covenant with you and with Israel.” Moses was there with the LORD forty days and forty nights without eating bread or drinking water. And he wrote on the tablets the words of the covenant—the Ten Commandments. When Moses came down from Mount Sinai with the two tablets of the covenant law in his hands, he was not aware that his face was radiant because he had spoken with the LORD.