Surah An-Naml 27:71

وَيَقُولُونَ مَتَىٰ هَـٰذَا ٱلْوَعْدُ إِن كُنتُمْ صَـٰدِقِينَ

And they say, "When is [the fulfillment of] this promise, if you should be truthful?"

Translation: Saheeh International

Tafsir

And they say ‘When will this promise of chastisement be if you are truthful?’ regarding it.

Excerpt from Tafsir al-Jalalayn, commentary on 27:71, via Quran.com. The reader has the full commentary and 9 more tafsirs.