Parashas Masei · Passuk 35:5 · TT note 1
Chabad.org — English translation + Rashi
Torah Temimah points to Nedarim 56b (TT note on “וּמַדֹּתֶם מִחוּץ לָעִיר”).
English: One who vows [to abstain] from a city is permitted to enter its techum. What is the reason? Because it is written with respect to its techum “and you shall measure from outside the city,” teaching that the techum of the city is not regarded as the city itself.
Halakhic definition of the city versus its measured outskirts for the law of vows.
The two-thousand-cubit migrash measured “from outside the city” is not part of the city for a neder; one who forswore the city may still enter the techum.