The Messenger of Allah ﷺ used to deliver two khutbahs standing, and he would separate them by sitting. (Using translation from Nasāʾī 1416)  

أَنَّ رَسُولَ اللهِ ﷺ «كَانَ يَخْطُبُ الْخُطْبَتَيْنِ وَهُوَ قَائِمٌ وَكَانَ يَفْصِلُ بَيْنَهُمَا بِجُلُوسٍ»  

[Machine] And Allah, blessed and exalted, said: "And when they see some merchandise or some amusement, they disperse to it and leave you standing." (Surah Al-Jumu'ah, 11)  

وَقَالَ اللهُ تَبَارَكَ وَتَعَالَى {وَإِذَا رَأَوْا تِجَارَةً أَوْ لَهْوًا انْفَضُّوا إِلَيْهَا وَتَرَكُوكَ قَائِمًا} [الجمعة 11]