Imam standing during the Khutbah

It was narrated that Simak said:

"I asked Jabir: 'Did the Messenger of Allah ﷺ deliver the Khutbah standing?' He said: 'The Messenger of Allah ﷺ used to deliver the Khutbah standing, then he would sit for a while, then stand up again.'"

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