Eruv techumin

An eruv techumin (Hebrew: עירוב תחומין, "mixed borders") for traveling enables Jews to travel on Shabbat or a Jewish holiday, without violating the prohibition of techum shabbat.

They prepare food prior to Shabbat or the holiday on which they plan to travel farther than is normally allowed on such days.

If they need to travel farther than that, they can leave some food in a certain location prior to that holiday or Sabbath.

Even so, this was a special allowance, and was only permitted in order to perform a mitzvah or avoid a danger.

[3] Since the Sabbath day limit of 2,000 cubits was a rabbinic ordinance, the Rabbis had the power to exercise leniency in what concerns its proper observance.