Quran 5:73 from Surah Al-Maaida on Divine Marvels.
لَّقَدۡ كَفَرَ ٱلَّذِينَ قَالُوٓاْ إِنَّ ٱللَّهَ ثَالِثُ ثَلَٰثَةٖۘ وَمَا مِنۡ إِلَٰهٍ إِلَّآ إِلَٰهٞ وَٰحِدٞۚ وَإِن لَّمۡ يَنتَهُواْ عَمَّا يَقُولُونَ لَيَمَسَّنَّ ٱلَّذِينَ كَفَرُواْ مِنۡهُمۡ عَذَابٌ أَلِيمٌ
English translation: Certainly disbelieved those who say Indeed Allah (is the) third (of) three And (there is) no [of] god except (the) God (the) One And if not they desist from what they are saying surely will afflict those who disbelieved among them a punishment painful
Transliteration: laqad kafara alladhina qalu inna al-laha thalithu thalathatin wama min ilahin illa ilahun wahidun wa-in lam yantahu amma yaquluna layamassanna alladhina kafaru min'hum adhabun alimun