Quran 30:51 from Surah Ar-Room on Divine Marvels.
وَلَئِنۡ أَرۡسَلۡنَا رِيحٗا فَرَأَوۡهُ مُصۡفَرّٗا لَّظَلُّواْ مِنۢ بَعۡدِهِۦ يَكۡفُرُونَ
English translation: But if We sent a wind and they see it turn yellow certainly they continue after it after it (in) disbelief
Transliteration: wala-in arsalna rihan fara-awhu mus'farran lazallu min ba'dihi yakfuruna