Bava Batra 8a:
Rab Judah said: All must contribute to the building of doors in the town gates, even orphans; not, however, the Rabbis, [since] they do not require protection....R. Assi further said in the name of R. Johanan: All are required to contribute to the repair of the town walls, including orphans, but not the Rabbis, because the Rabbis do not require protection. R. Papa said: For the repair of the walls, for the horse-guard and for the keeper of the armoury even orphans have to contribute, but the Rabbis [do not, since they] do not require protection.
Or the key phrase in Aramaic: אבל מרבנן לא רבנן לא צריכי נטירותא
There is a famous story, which can be found in Yerushalmi Chagiga 6a-b, about the Rabbis, or rather teachers, being the protectors of the city.
I recall hearing from Dr. Steiner* that it was funny, from a grammatical standpoint, that the Neturei Karta call themselves the Neturei Karta. If one wanted to say protectors of the city in Aramaic, it should be Netorei Karta, with a cholam**. With Neturei Karta appearing to be the passive, and those those who were protected, rather than the protectors. Of course, he clarified, that is not how it would work in Aramaic. The "protected" would be Netirei Karta, with a chirik. Which after all is their Chassidic pronunciation of Neturei, so that it works out after all.
(Presumably, the same applies to Charovei Karta...)
* though I heard it years ago, and so any errors in what I report are almost certainly due to my deficiency in recollection.
** and thus also against the vocalization provided to the right.