Do Not Go Outside of the Boundary on Shabbat

(13) In the evening quail appeared and covered the camp; in the morning there was a fall of dew about the camp. (14) When the fall of dew lifted, there, over the surface of the wilderness, lay a fine and flaky substance, as fine as frost on the ground. (15) When the Israelites saw it, they said to one another, “What is it?” (man hu?)—for they did not know what it was. And Moses said to them, “That is the bread which the LORD has given you to eat. (16) This is what the LORD has commanded: Gather as much of it as each of you requires to eat, an omer to a person for as many of you as there are; each of you shall fetch for those in his tent.” (21) So they gathered it every morning, each as much as he needed to eat; for when the sun grew hot, it would melt. (22) On the sixth day they gathered double the amount of food, two omers for each; and when all the chieftains of the community came and told Moses, (23) he said to them, “This is what the LORD meant: Tomorrow is a day of rest, a holy sabbath of the LORD. Bake what you would bake and boil what you would boil; and all that is left put aside to be kept until morning.” (24) So they put it aside until morning, as Moses had ordered; and it did not turn foul, and there were no maggots in it. (25) Then Moses said, “Eat it today, for today is a sabbath of the LORD; you will not find it today on the plain. (26) Six days you shall gather it; on the seventh day, the sabbath, there will be none.” (27) Yet some of the people went out on the seventh day to gather, but they found nothing. (28) And the LORD said to Moses, “How long will you men refuse to obey My commandments and My teachings? (29) Mark that the LORD has given you the sabbath; therefore He gives you two days’ food on the sixth day. Let everyone remain where he is: let no one leave his place on the seventh day.” (30) So the people remained inactive on the seventh day.

[Parshat] Vayehi Beshalach Pharaoh has one negative commandment in it. That we should not go outside of the boundary (techum - domain, confines, realm, scope area) on Shabbat: That we have been prevented from going outside of the known boundaries on Shabbat, as it is stated (Exodus 16:29), "let no one leave his place on the seventh day." And the explanation comes about this that "his place" is called anywhere that is no further than three parsa from outside of the city (Mishneh Torah, Laws of Sabbath 27:1-2) (note: Hebrew for "place" is Makom which is another word for God, so there are implications here that one should not leave his or her God on Shabbat). And a parsa is four mil, and a mil is two thousand ells. And we measure it from the outermost house in the city, even if it is as large as Nineveh. This is according to the law of the Torah, but the Sages made a fence (around the Torah) and forbade that one should walk more than two thousand ells (approx. .92 miles) outside of the city.

(If you want to go into great detail)

The laws of the commandment - for example, what is the law about one who spends Shabbat in the wilderness or in a cave (Eruvin 61b); and so [too,] one who goes outside of the boundary - volitionally or inadvertently, or by permission of the court (Eruvin 52b); what is the law if he surrounded himself with a partition on Shabbat (Eruvin 42a); what are the laws regarding the city of a house that goes out more than the other houses of the city seventy ells and a bit, a synagogue that has a domicile for the sextons, a house of idolatry that has domiciles for priests, or storehouses that have domiciles or three barriers that do not have a roof or pitch (Eruvin 55b); and how one measures a long or square or round city, or one that is made like the shape of a gamma or like an arch (Eruvin 55a); and with which string do we measure; and what is the size of the string (Eruvin 53b); and how does one measure from one valley to [another] valley, or to a mountain or to a wall; and upon whom do we rely for the measurement; and who is [considered] trustworthy to testify about the boundaries; and the rest of its details - are [all] found in the tractate that is built upon it, and that is Eruvin.

From the roots of this commandment are that we should remember and know that the world is created and not primordial, as it is written explicitly about the commandment of Shabbat (Exodus 20:11), "For in six days the Lord made the heavens and the earth, the sea and all that is in them, and He rested on the seventh day." Hence to remember this thing, it is fitting that we rest in one place; meaning to say that we not go to a faraway place, but rather only stroll and have delight. And the walking of [up to] twelve mil (the limit of what is allowed by the Torah) does not have much strain to it.