The Prophet ﷺ used to deliver two sermons. He would sit down when he ascended the pulpit till he (I think he meant the mu'adhdhin) finished. He would then stand up and preach, then sit down and say nothing, then stand up and preach.  

كَانَ النَّبِيُّ ﷺ يَخْطُبُ خُطْبَتَيْنِ كَانَ يَجْلِسُ إِذَا صَعِدَ الْمِنْبَرَ حَتَّى يَفْرُغَ أُرَاهُ قَالَ الْمُؤَذِّنُ ثُمَّ يَقُومُ فَيَخْطُبُ ثُمَّ يَجْلِسُ فَلاَ يَتَكَلَّمُ ثُمَّ يَقُومُ فَيَخْطُبُ