Rashi on Leviticus 25:23/רש"י על ויקרא כ״ה:כ״ג

1‎‎לא תמכר‎‎ והארץ THE LAND SHALL NOT BE SOLD [ABSOLUTELY] — This is intended to charge with the transgression of a negative command (לאו) the neglect of returning the fields to their owners in the Jubilee — it commands that the purchaser must not detain it (Sifra, Behar, Chapter 5 8).

2לצמתת means for severance; the meaning is: it shall not be sold as a sale that severs in perpetuity.

3כי לי הארץ FOR THE LAND IS MINE — Your eye shall not be evil towards it (you shall not begrudge this) for it is not yours.