TT #169 · Parashas Shoftim · Fourth Aliyah · Passuk 18:08
They shall eat equal portions, aside from what is his by sale according to the fathers.
Torah Temimah points to Sifrei Devarim 169 / Chullin related.
TT lemma: חֵלֶק כְּחֵלֶק יֹאכֵלוּ.
Sefaria — Sifrei Devarim 169 / Chullin related
English: ‘They shall eat equal portions’ – that they shall divide equally.
Derash on equal shares (Sifrei) — the language requires parity in the distribution of the sacred portions.
When a Levi comes to serve, he receives an equal share of the portions with the Leviim already present, except for ancestral property rights.