Surah Taha — Ayah 129 (20:129)

English translation (Saheeh International)

And if not for a word¹ that preceded from your Lord, it [i.e., punishment] would have been an obligation [due immediately],² and [if not for] a specified term [decreed].

1. See footnote to 10:19.
2. Allāh would have punished the disbelievers in this world as He did with previous peoples.

Brief commentary

O Messenger, had a word not preceded from your Lord that He will not punish anyone before establishing the proof against him, and had there not been a time which is fixed with Him, the punishment would have come to them quickly, due to their deserving it.