أَخْبَرَنَا إِسْمَاعِيلُ بْنُ مَسْعُودٍ، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ سِمَاكٍ، قَالَ سَأَلْتُ جَابِرًا أَكَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَخْطُبُ قَائِمًا قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَخْطُبُ قَائِمًا ثُمَّ يَقْعُدُ قَعْدَةً ثُمَّ يَقُومُ ‏.‏

It was narrated that Simak said: "I asked Jabir: 'Did the Messenger of Allah (PBUH) deliver the Khutbah standing?' He said: 'The Messenger of Allah (PBUH) used to deliver the Khutbah standing, then he would sit for a while, then stand up again.'" Translation Not Available

Book Ref: Sunan An Nisai Book 19 Hadith 1574
Web Ref:  Sunan An Nisai Vol 2 Book 19 Hadith 1575