Where does the pattern of six days of work and one day of rest come from?
The pattern comes from Genesis chapter 1, where God brought everything onto the scene in six days and rested on the seventh. That set up six days of labor and one day of rest. It is also instituted in Exodus 16, before the law, when Israel gathered double manna on the sixth day for the Sabbath.
Les explains that the Sabbath command was instituted before the law was given at Sinai, since Exodus 20 comes later. In Exodus 16, God instructed Israel to gather a double portion of manna on the sixth day because the seventh day would be the rest of the holy Sabbath. Les ties this back to Genesis chapter 1, where God brought everything onto the scene in six days and rested on the seventh. He was not tired, but was setting something up for man's own good. Les says God still knows what's best for us: one day out of seven for rest, carrying into our own economy.
And God saw every thing that he had made, and, behold, it was very good. And the evening and the morning were the sixth day.
And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made.