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””"
SahihSahihSahih MuslimBook 19 · Hadith 19