Jabir b. Samura said, “The Prophet (ﷺ) used to preach standing, then he would sit down, then stand and preach standing. If anyone tells you he preached sitting he is lying. I swear by God that I prayed along with him on more than two thousand occasions.” Muslim transmitted it.

عَنْ جَابِرِ بْنِ سَمُرَةَ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَخْطُبُ قَائِمًا ثُمَّ يَجْلِسُ ثُمَّ يَقُومُ فَيَخْطُبُ قَائِمًا فَمَنْ نَبَّأَكَ أَنَّهُ كَانَ يَخْطُبُ جَالِسًا فَقَدْ كَذَبَ فَقَدَ وَالله صليت مَعَه أَكثر من ألفي صَلَاة. رَوَاهُ مُسلم