Exodus 34:27-28

27Then the Lord said to Moses, ‘Write down these words. They are the rules of the covenant that I have made with you and with the Israelites.’

28Moses was there on the mountain with the Lord for 40 days and 40 nights. He did not eat anything or drink anything during that time. He wrote the words of God's covenant on the flat stones. Those were God's ten special commands.