Quran 2:13 from Surah Al-Baqara on Divine Marvels.
وَإِذَا قِيلَ لَهُمۡ ءَامِنُواْ كَمَآ ءَامَنَ ٱلنَّاسُ قَالُوٓاْ أَنُؤۡمِنُ كَمَآ ءَامَنَ ٱلسُّفَهَآءُۗ أَلَآ إِنَّهُمۡ هُمُ ٱلسُّفَهَآءُ وَلَٰكِن لَّا يَعۡلَمُونَ
English translation: And when it is said to them Believe as believed the people they say Should we believe as believed the fools Beware certainly they themselves (are) the fools [and] but not they know
Transliteration: wa-idha qila lahum aminu kama amana al-nasu qalu anu'minu kama amana al-sufahau ala innahum humu al-sufahau walakin la ya'lamuna