Tafsir of Ash-Shu`ara' 26:130

{And when you strike}—that is, when you intend to strike with a whip or a sword—{you strike as tyrants}—that is, overpowering and oppressive, without mercy, without the intent of discipline, and without regard for the consequence.

The beginning of the conditional clause with what has been mentioned [i.e., the repetition of the verb] is for the sake of indicating causation. Qualifying the consequence [the result of the condition] with the current state [the state of being tyrants]—its correctness is not confirmed [by those who argue otherwise], because the absolute [the first act of striking] is not a cause for the qualified [the act of striking with tyranny]. It is said: The identity [between the condition and the consequence] is not harmful, for the sake of hyperbole. It is also said: The retaliatory nature [of the conditional structure] is in consideration of notification and informing, which is, as you see, similar to the verse and the saying:

When you ignite it, you ignite it as something unsightly.

His (peace be upon him) rebuke of them with what has been mentioned indicates that the love of this world and arrogance had overcome their hearts, until that had cast them out of the bounds of servitude.