Ka'b b. ‘Ujra said he entered the mosque when ‘Abd ar-Rahman b. Umm al-Hakam was sitting while he preached, and said:

Look at this scoundrel who is sitting while he preaches, though God most high has said, “But when they see merchandise or diversion they disperse to it and leave you standing” (Al-Qur’an; 62:11). Muslim transmitted it.

وَعَنْ كَعْبِ بْنِ عُجْرَةَ: أَنَّهُ دَخَلَ الْمَسْجِدَ وَعَبْدُ الرَّحْمَنِ بْنُ أُمِّ الْحَكَمِ يَخْطُبُ قَاعِدًا فَقَالَ: انْظُرُوا إِلَى هَذَا الْخَبِيثِ يَخْطُبُ قَاعِدًا وَقد قَالَ الله تَعَالَى: (وَإِذَا رَأَوْا تِجَارَةً أَوْ لَهْوًا انْفَضُّوا إِلَيْهَا وَتَرَكُوك قَائِما) رَوَاهُ مُسلم