Sura al-Baqara 2:14

وَإِذَا لَقُوا۟ ٱلَّذِينَ ءَامَنُوا۟ قَالُوٓا۟ ءَامَنَّا وَإِذَا خَلَوْا۟ إِلَىٰ شَيَٰطِينِهِمْ قَالُوٓا۟ إِنَّا مَعَكُمْ إِنَّمَا نَحْنُ مُسْتَهْزِءُونَ

wa-idhā laqū lladhīna āmanū qālū āmannā wa-idhā khalaw ilā shayāṭīnihim qālū innā maʿakum innamā naḥnu mustahziʾūna

When they meet those who believe, they say: "We believe;" but when they are alone with their evil ones, they say: "We are really with you: We (were) only jesting."