Here, then, the seventh-day Sabbath was distinctly singled out and held apart from all the other days of the week by the fact, first: that the manna would not keep over to any other day than the seventh-day Sabbath, by which fact they were excluded from using or keeping any more than a single daily portion for each individual; second: on the seventh day, which is the Sabbath, and on that day alone, would any portion keep, beyond the single daily portion for each individual, and, in view of this fact, a double portion was gathered on the sixth day;
third: there was no manna given on the seventh day, which is the Sabbath.
---Thus, by these specific facts, which were directly and wholly controlled by the Lord Himself, the seventh day, which is the Sabbath, was distinctly designated.
And that all this was not only without their choice, but even against their choice, is plain from the fact that, though for all the days except the seventh day, which is the Sabbath, they were commanded not to leave any of it till the morning, yet they disregarded the command, and would have their own way, and left some of it till the morning. But, by causing to spoil all that they had so carefully laid up, the Lord instructed them that His word means exactly what it says."
A.T. Jones