TT #220 · Parashas Shoftim · Sixth Aliyah · Passuk 19:14
You shall not move your fellow’s boundary marker, which the first ones set, in your inheritance that you will inherit in the land that the Eternal your God is giving you to possess.
Torah Temimah points to Sifrei Devarim 188 / Bava Basra.
TT lemma: לֹא תַסִּיג גְּבוּל רֵעֲךָ.
Sefaria — Sifrei Devarim 188 / Bava Basra
English: ‘You shall not move your fellow’s boundary marker’ – a prohibition against one who moves a boundary.
Derash establishing the prohibition (Sifrei / Bavli) — the language creates a distinct negative commandment.
It is forbidden to move a neighbor’s boundary marker. This is a distinct prohibition protecting property rights in the Land.