Quran 4:137 from Surah An-Nisaa on Divine Marvels.
إِنَّ ٱلَّذِينَ ءَامَنُواْ ثُمَّ كَفَرُواْ ثُمَّ ءَامَنُواْ ثُمَّ كَفَرُواْ ثُمَّ ٱزۡدَادُواْ كُفۡرٗا لَّمۡ يَكُنِ ٱللَّهُ لِيَغۡفِرَ لَهُمۡ وَلَا لِيَهۡدِيَهُمۡ سَبِيلَۢا
English translation: Indeed those who believed then disbelieved then (again) believed then disbelieved then increased (in) disbelief not will Allah forgive [for] them and not will guide them (to) a (right) way
Transliteration: inna alladhina amanu thumma kafaru thumma amanu thumma kafaru thumma iz'dadu kuf'ran lam yakuni al-lahu liyaghfira lahum wala liyahdiyahum sabilan