Tafsir of Ar-Rahman 55:8

Ar-Rahman (The Most Merciful): (8) Lest you transgress in the balance...

Regarding the interpretation of the two balances (Mizan):

It has been suggested that the first Mizan (Balance) refers to Justice, and its establishment refers to the Law (Shari'ah). This implies: "God legislated Justice so that you do not transgress in the Mizan (Balance), which is the instrument of justice." This is the reported view.

However, it is preferable to reverse the order: The first Mizan is the instrument (the physical scale), and the second Mizan means the source/act (the verbal noun, masdar).

This means: "He established the instrument (the scale) so that you do not transgress in weighing (the act of measuring), or so that you do not transgress in Justice (giving every deserving person their due right)."

It is also permissible to interpret Mizan as the masdar (source/act), similar to how Mithaq (covenant) can mean Wuthūq (firmness), or Mī'ād (promise) can mean Wa'd (promising). In this case, the Mizan refers to the instrument of weighing.

The Second View:

The word an (that) in "Lest you transgress" is explanatory (mufassirah). The implied meaning is: "He established Justice, meaning: Do not transgress." Thus, establishing the Mizan means establishing Justice. Applying the term Wad'u (establishment) to the Law and Mizan to Justice is permissible. It is also possible that "establishing the Mizan" means establishing the act of weighing.

Regarding the phrase: {Lest you transgress in the balance}

On this interpretation, the intended meaning of Mizan is weighing. It is essentially a prohibition against transgression in the act of weighing and balancing.

The repetition of the word Mizan (Balance) indicates that both instances refer to the same concept. It is as if He said: "Lest you transgress in it [the balance/weighing]."

If one asks: "If the intention was weighing, why did He not say: 'Lest you transgress in weighing (al-wazn)'?"

We reply: If He had said al-wazn, it might have been assumed that the prohibition was restricted only to weighing for others (i.e., cheating others), and not to maintaining balance for oneself. By using the term al-Mizan (the instrument), which encompasses both taking and giving, it covers all aspects. This is because if the giver weighs and clearly tips the scale in their favor, they have engaged in usury (arba), especially in transactions involving equivalent items (like currency exchange or bartering like for like).