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."
The Saheeh International Quran Translation
قُلْ هُوَ ٱلرَّحْمَٰنُ ءَامَنَّا بِهِۦ وَعَلَيْهِ تَوَكَّلْنَا فَسَتَعْلَمُونَ مَنْ هُوَ فِى ضَلَٰلٍ مُّبِينٍSay, "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."