The fields of common land belonging to their cities: this whole expression more than likely refers to the unenclosed pasture land surrounding the cities of the Levites.

Be sold: this passive will have to be translated actively in many languages. And this will require a restructuring of the verse. A possible model may be “No one can ever sell the pasture land…,” or “The Levites may never sell…,” or “No one may buy … from the Levites.”

It is their perpetual possession: that is, they do not have the right to sell this land even for a limited period of time. This may be expressed as “it must always belong to them,” or “it must remain permanently in the hands of the Levites,” or “it must always belong to the priestly family.” This is in contrast with their houses, which could be temporarily sold to persons outside the priestly class.

Quoted with permission from Péter-Contesse, René and Ellington, John. A Handbook on Leviticus. (UBS Helps for Translators). New York: UBS, 1990. For this and other handbooks for translators see here .