Rashi on Leviticus 19:36/רש"י על ויקרא י״ט:ל״ו

1אבני צדק are stones used for weights wherewith one weighs.

2איפת — The “Epha” is a certain dry measure.

3והין — The “Hin” is a certain liquid measure.

4אשר הוצאתי אתכם WHO BROUGHT YOU FORTH [FROM EGYPT] for this purpose, that you shall be honest in your actions (Sifra, Kedoshim, Chapter 8 10). Another explanation is: I distinguished in Egypt between those who were firstborn and those who were not firstborn (a matter which is hidden from human cognizance), I am also certain to exact punishment from him who secretly puts his weights in salt in order to take advantage of people who are not aware of it (cf. Bava Metzia 61b).