The Prophet ﷺ used to deliver two sermons, sitting between them, during which he would recite the Quran and remind the people.In another narration, the Messenger of Allah ﷺ would deliver the sermon standing, then sit down, then stand again and deliver another sermon standing. Whoever told you that he used to deliver the sermon sitting has lied. By Allah, I prayed behind him more than two thousand prayers.
كانت للنبي ﷺ خطبتان يجلس بينهما يقرأ القرآن، ويذكر الناس. وفي رواية: أن رسول الله ﷺ كان يخطب قائما ثم يجلس، ثم يقوم فيخطب قائما، فمن نبأك أنه كان يخطب جالسا فقد كذب، فقد والله صليت معه أكثر من ألفي صلاة.
Muslim narrated it in the Jumuah chapter (862) via Abu Ahwas, from Simak, from Jabir bin Samura, and he related the hadith. The second narration he related via Abu Khaythama, from Simak. In a narration found in Abu Dawud (1095), "I saw the Messenger of Allah ﷺ deliver the sermon standing, then sit for a pause during which he did not speak." Its chain of transmission is sahih. His statement, "I prayed with him more than two thousand prayers," refers to the five daily prayers, including the Friday prayer.On this subject there is also a report from Saaib bin Yazid, that the Prophet ﷺ used to deliver two sermons on Friday, sitting between them. Tabarani narrated it in Al-Kabir (6661) via Muhammad bin Ishaq, from Zuhri, from Saaib bin Yazid. But Ibn Ishaq is a mudallis, and here he narrated using "an" (without stating direct transmission).