Here is mention of a seventh-day sabbath. It was known, not only before the giving of the law upon mount Sinai, but before the bringing of Israel out of Egypt, even from the beginning, Ge 2:3. The setting apart one day in seven for holy work, and, in order to that, for holy rest, was ever since God created man upon the earth, and is the most ancient of the Divine laws.
Appointing them to rest on the seventh day, he took care that they should be no losers by it; and none ever will be losers by serving God. On that day they were to fetch in enough for two days, and to make it ready.
This directs us to contrive family affairs, so that they may hinder us as little as possible in the work of the sabbath. Works of necessity are to be done on that day; but it is desirable to have as little as may be to do, that we may apply ourselves the more closely to prepare for the life that is to come.
When they kept manna against a command, it stank; when they kept it by a command, it was sweet and good; every thing is sanctified by the word of God and prayer. On the seventh day God did not send the manna, therefore they must not expect it, nor go out to gather.
This showed that it was produced by miracle.