申命記 25:13

אבן ואבן [THOU SHALT NOT HAVE IN THY BAG] DIVERSE STONES — i.e., weights. גדולה וקטנה A GREAT AND A SMALL — i.e. thou shalt not have a large one that contradicts the small one, — that one must not buy (lit., take) goods by the larger and sell (lit., give it back) by the smaller (Sifrei Devarim 294:1).

לֹֽא־יִהְיֶ֥ה לְךָ֛ בְּכִֽיסְךָ֖ אֶ֣בֶן וָאָ֑בֶן גְּדוֹלָ֖ה וּקְטַנָּֽה׃

Thou shalt not have in thy bag divers weights, a great and a small.