"Abu Rifa'ah said: 'I came to the Messenger of Allah [SAW] while he was delivering a Khutbah, and said: "O Messenger of Allah, a stranger has come to ask about his religion, for he does not know what his religion is." The Messenger of Allah [SAW] stopped delivering his Khutbah and turned to me. A chair was brought, and I think its legs were of iron. The Messenger of Allah [SAW] sat down on it and started to teach me what Allah has taught him, then he went and completed his Khutbah.'" (Using translation from Nasāʾī 5377)  

قَالَ أَبُو رِفَاعَةَ انْتَهَيْتُ إِلَى رَسُولِ اللهِ ﷺ وَهُوَ يَخْطُبُ فَقُلْتُ «يَا رَسُولَ اللهِ رَجُلٌ غَرِيبٌ جَاءَ يَسْأَلُكَ عَنْ دِينِهِ لَا يَدْرِي مَا دِينُهُ» فَأَقْبَلَ رَسُولُ اللهِ ﷺ وَتَرَكَ خُطْبَتَهُ حَتَّى انْتَهَى إِلَيَّ فَأُتِيَ بِكُرْسِيٍّ خِلْتُ قَوَائِمَهُ حَدِيدًا فَقَعَدَ رَسُولُ اللهِ ﷺ فَجَعَلَ يُعَلِّمُنِي مِمَّا عَلَّمَهُ اللهُ ثُمَّ أَتَى خُطْبَتَهُ فَأَتَمَّهَا