‘And he said to them, “This is that which Yahweh spoke. Tomorrow is a solemn rest, a holy sabbath to Yahweh. Bake what you will bake and seethe what you will seethe and all that remains over lay up for yourselves to be kept until the morning.” '
The impression given here is that Moses is imparting new information. He explains that the seventh day is to be a holy sabbath, and therefore also every seventh day after that. It may well therefore be that this is in fact the time when the regular seventh day sabbath was first established, in order to commemorate the giving of the Manna as something better than the bread of Egypt. Previously holy rest days had been mentioned (Exodus 12:16) although not called sabbaths.
Because it is a sabbath (shabbath) they are to rest on it. It is a holy rest (shabbathon). This would hardly need to be explained if they were familiar with it. Moses elsewhere tells us that the reason why God commanded the observance of the regular seventh day sabbath was because He had delivered them from the land of Egypt (in Deuteronomy 5:15). This also would tie in with a post-deliverance establishment of the Sabbath. The Creation account says nothing about the Sabbath.
“Shabbathon”, ‘a solemn rest' is a word only used of observance of the Sabbath (shabbath).
So while no indication is specifically given as to whether this is a new observance on each seventh day or the perpetuation of what was already the custom, the probability seem to lie with the former. The sabbath has not previously been mentioned, and the only mention of a seventh day feast previously is Exodus 13:6 and there it would not in future be on the same day of ‘the week' each year, as it was tied to the 14th-21st of Abib, and new moons did not follow an exact twenty eight day pattern. And in that feast there was also a special feast on the first day of the feast as well as the seventh. It may well be therefore that this incident of the Manna is the first establishing of the strict seven day week pattern and of the regular Sabbath. Previously they may simply have utilised periods of the moon for recording time, or simply followed the ways of the Egyptians.
Indeed had the Sabbath and the seven day week already been a well recognised feature we might have expected that those who broke it (Exodus 16:27) would be put to death (see Numbers 15:32-36). Instead they were only rebuked for having disobeyed the command not to gather.
It is also interesting to note that there is no specific emphasis here of doing no work, although it may possibly be seen as implied in Exodus 16:23 and Exodus 16:26-27, the latter only being stated, however, after the failure to observe the Sabbath. This may again be why they were only rebuked.
But its introduction was probably made easier by the fact that ‘seven days' (not then directly related to our week) was often seen as a holy period (see Genesis 7:4; Genesis 7:10; Genesis 8:10; Genesis 8:12; Genesis 8:22; Genesis 29:27-28; Genesis 50:10; Exodus 7:25; Exodus 12:15; Exodus 12:19; Exodus 13:6-7 and often). Seven was the number of divine perfection. Thus from now on their life was in a sense to be made up of many holy periods in which God provided their food. Instead of being controlled by sun and moon, their time was now divinely controlled.
It is true that in Genesis 2:1-3 God stopped working on ‘the seventh day' from all His activity in creation, but that is not applied there to the requirement for man to observe it, and had it been a requirement when that was written we would have expected it to be mentioned. Nor is the seventh day there called the sabbath (although shabbath is related to shabath, to stop, be at a standstill, stop working which is used there). Later in Exodus 20:10 (see also Exodus 31:17) this example is given as proving that the idea of the seventh day was something which God has blessed but there is no necessary suggestion or indication that the sabbath itself was inaugurated at the time of creation. As we have seen, in Deuteronomy 5:14-15 it is the deliverance from Egypt that is given as the reason why God instituted the Sabbath. The bondmen had become free and in gladness and gratitude would honour Yahweh by dedicating a work-free day to Him.
Attempts have been made to link the sabbath with the Babylonian ‘sabbatum', but that was on the day of the full moon and not a day of rest or cessation from work, (this is revealed by contract tablets), and they had a five-day week. Ceasing of work on certain days in the Assyrian period by certain limited important people such as kings and priests was simply due to a desire to ward off bad luck.
“Bake what you will bake and boil what you will boil.” This makes clear that the Manna was cooked before eating. On the sixth day they would presumably do all the cooking, and set aside what had not been eaten for the morrow.