Sunan an-Nasa'i 1583
سنن النسائي#1583Hasanأَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ سِمَاكٍ، عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَخْطُبُ قَائِمًا ثُمَّ يَقْعُدُ قَعْدَةً لاَ يَتَكَلَّمُ فِيهَا ثُمَّ قَامَ فَخَطَبَ خُطْبَةً أُخْرَى فَمَنْ خَبَّرَكَ أَنَّ النَّبِيَّ صلى الله عليه وسلم خَطَبَ قَاعِدًا فَلاَ تُصَدِّقْهُ .
It was narrated that Jabir bin Samurah said:"I saw the Messenger of Allah (ﷺ) delivering the Khutbah standing up, then he sat down for a while and did not speak, then he stood up and delivered another Khutbah. Whoever tells you that the Prophet (ﷺ) delivered a Khutbah sitting do not believe him
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 19:28