Authentic
Sahih Muslim 876
I came to the Messenger of Allah (may Allah's peace and blessings be upon him) while he was giving a sermon
Abu Rifā‘ah Tamīm ibn Usayd (may Allah be pleased with him) reported: I came to the Messenger of Allah (may Allah’s peace and blessings be upon him) while he was giving a sermon, and I said: "O Messenger of Allah, a stranger (meaning himself) has come to inquire about his religion. He is quite…
فَأُتِيَ بِكُرْسِيٍّ حَسِبْتُ قَوَائِمَهُ حَدِيدًا - قَالَ - فَقَعَدَ عَلَيْهِ رَسُولُ اللَّهِ صلى الله عليه وسلم وَجَعَلَ يُعَلِّمُنِي مِمَّا عَلَّمَهُ اللَّهُ ثُمَّ أَتَى خُطْبَتَهُ فَأَتَمَّ آخِرَهَا .