21 “Six days you shall work, but on the seventh day you shall rest. In plowing time and in harvest you shall rest. 22 You shall observe the Feast of Weeks, the firstfruits of wheat harvest, and the Feast of Ingathering at the year's end. 23 Three times in the year shall all your males appear before the Lord God, the God of Israel. 24 For I will cast out nations before you and enlarge your borders; no one shall covet your land, when you go up to appear before the Lord your God three times in the year.
25 “You shall not offer the blood of my sacrifice with anything leavened, or let the sacrifice of the Feast of the Passover remain until the morning. 26 The best of the firstfruits of your ground you shall bring to the house of the Lord your God. You shall not boil a young goat in its mother's milk.”
27 And the Lord said to Moses, “Write these words, for in accordance with these words I have made a covenant with you and with Israel.” 28 So he was there with the Lord forty days and forty nights. He neither ate bread nor drank water. And he wrote on the tablets the words of the covenant, the Ten Commandments. 
29 When Moses came down from Mount Sinai, with the two tablets of the testimony in his hand as he came down from the mountain, Moses did not know that the skin of his face shone because he had been talking with God.  30 Aaron and all the people of Israel saw Moses, and behold, the skin of his face shone, and they were afraid to come near him. 31 But Moses called to them, and Aaron and all the leaders of the congregation returned to him, and Moses talked with them. 32 Afterward all the people of Israel came near, and he commanded them all that the Lord had spoken with him in Mount Sinai. 33 And when Moses had finished speaking with them, he put a veil over his face.
34 Whenever Moses went in before the Lord to speak with him, he would remove the veil, until he came out. And when he came out and told the people of Israel what he was commanded, 35 the people of Israel would see the face of Moses, that the skin of Moses' face was shining. And Moses would put the veil over his face again, until he went in to speak with him. (ESV)