Surah Ad-Dukhan 44:50

إِنَّ هَـٰذَا مَا كُنتُم بِهِۦ تَمْتَرُونَ

Indeed, this is what you used to dispute."

Translation: Saheeh International

Tafsir

And it will be said to them This that you see of the chastisement is indeed that which you used to doubt’ about which you used to be uncertain.

Excerpt from Tafsir al-Jalalayn, commentary on 44:50, via Quran.com. The reader has the full commentary and 9 more tafsirs.