Qur'an 2:76

وَإِذَا لَقُوا۟ ٱلَّذِينَ ءَامَنُوا۟ قَالُوٓا۟ ءَامَنَّا وَإِذَا خَلَا بَعْضُهُمْ إِلَىٰ بَعْضٍ قَالُوٓا۟ أَتُحَدِّثُونَهُم بِمَا فَتَحَ ٱللَّهُ عَلَيْكُمْ لِيُحَآجُّوكُم بِهِۦ عِندَ رَبِّكُمْ ۚ أَفَلَا تَعْقِلُونَ

“And when they meet those who believe, they say, "We have believed"; but when they are alone with one another, they say, "Do you talk to them about what Allāh has revealed to you so they can argue with you about it before your Lord?" Then will you not reason?”

Al-Baqara 2:76 · Saheeh International