Al-Baqarah 2:76

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

Behold! when they meet the men of Faith, they say: "We believe": But when they meet each other in private, they say: "Shall you tell them what Allah hath revealed to you, that they may engage you in argument about it before your Lord?"- Do ye not understand (their aim)?