Tafsir of Al-An'am 6:131-132

{That} is a reference to what preceded regarding the sending of messengers to them and warning them of an evil outcome. It is the predicate of an omitted subject; that is: "The matter is that."

{That your Lord would not destroy the cities} is a justification; meaning: The matter is what We have narrated to you, due to the negation of your Lord being one who destroys cities unjustly.

• The particle {أن} (that) is the one that governs the subjunctive mood for verbs.
• It is also permissible for it to be the "lightened" form of the "heavy" anna, meaning: "Because the affair and the discourse is that your Lord would not destroy the cities unjustly."
• You may also consider it a substitute (badal) for "that," as in His saying: “And We conveyed to him that matter: that those people would be cut off” (Al-Hijr: 66).

{Unjustly} means: because of an injustice they committed beforehand. Or, it means "being unjust," in the sense that if He were to destroy them while they were heedless and had not been alerted by a messenger or a scripture, it would be an injustice—and He is exalted above injustice and every ugly thing.

{And for all} of the morally responsible beings {are degrees}—ranks—{from what they have done}—from the recompense of their deeds.

{And your Lord is not unaware of what they do}—He is not forgetful of it, nor are its quantities, conditions, or the reward deserved for it hidden from Him.

{And your Lord is the Free of need, the Possessor of mercy. If He wills, He can do away with you and give succession after you to whatever He wills, just as He produced you from the descendants of another people. Indeed, what you are promised is coming, and you will not cause failure [to escape].}