Surah Al-Mulk 67:29

قُلْ هُوَ ٱلرَّحْمَـٰنُ ءَامَنَّا بِهِۦ وَعَلَيْهِ تَوَكَّلْنَا ۖ فَسَتَعْلَمُونَ مَنْ هُوَ فِى ضَلَـٰلٍ مُّبِينٍ

Say, "He is the Most Merciful; we have believed in Him, and upon Him we have relied. And you will [come to] know who it is that is in clear error."

Translation: Saheeh International

Tafsir

Say ‘He is the Compassionate One; we believe in Him and in Him we put our trust. And assuredly you will soon know sa-ta‘lamūna is also read sa-ya‘lamūna ‘they will know’ upon seeing the chastisement with your own eyes who is in manifest error’ is it us or yourselves or them?

Excerpt from Tafsir al-Jalalayn, commentary on 67:29, via Quran.com. The reader has the full commentary and 9 more tafsirs.