Tafsir of Al-Muddathir 74:19

Al-Muddaththir (74): Verse 19

فَقُتِلَ كَيْفَ قَدَّرَ (Then, may he be destroyed! How he determined!)

This phrase is used when expressing astonishment and magnification (of the matter being discussed). Similar expressions include: "May God destroy him, how brave he is!" or "May God disgrace him, how cunning he is!"

The meaning is that the person being described has reached a level worthy of envy, prompting the envier to invoke such a curse upon him.

Knowing this, we can state that this verse bears two possible interpretations here:

1. Astonishment at the strength of his (the denier's) reasoning: Meaning, it is impossible to find a flaw or objection against the matter of Prophet Muhammad (peace be upon him) with a suspicion greater or stronger than what this speaker has put forth.
2. Praise delivered through mockery (Istihzā'): Meaning, what this person has stated is utterly weak and contemptible.

Then He said:

ثُمَّ قُتِلَ كَيْفَ قَدَّرَ (Then, may he be destroyed! How he determined!)