Quran 40:70 from Surah Ghafir on Divine Marvels.
ٱلَّذِينَ كَذَّبُواْ بِٱلۡكِتَٰبِ وَبِمَآ أَرۡسَلۡنَا بِهِۦ رُسُلَنَاۖ فَسَوۡفَ يَعۡلَمُونَ
English translation: Those who deny the Book and with what We sent with it Our Messengers but soon they will know
Transliteration: alladhina kadhabu bil-kitabi wabima arsalna bihi rusulana fasawfa ya'lamuna