"And it has already been revealed to you in the Book that if you hear the verses of Allah being disbelieved and mocked, then do not sit with them until they engage in a different conversation." This means: what was revealed in Surat al-An'am: "And when you see those who engage in [offensive] discourse concerning Our verses, then turn away from them..." until the end of the verse.
﴿وَقَدْ نَزَّلَ عَلَيْكُمْ فِي الْكِتَابِ أَنْ إِذَا سَمِعْتُمْ آيَاتِ اللَّهِ يُكْفَرُ بِهَا وَيُسْتَهْزَأُ بِهَا فَلا تَقْعُدُوا مَعَهُمْ حَتَّى يَخُوضُوا فِي حَدِيث غَيره﴾ يَعْنِي: مَا أنزل فِي سُورَة الْأَنْعَام: ﴿وَإِذَا رَأَيْتَ الَّذِينَ يَخُوضُونَ فِي آيَاتنَا فَأَعْرض عَنْهُم﴾ الْآيَة.
