Tamim bin Usaid (May Allah be pleased with him) reported:
I came to Messenger of Allah (ﷺ) while he was delivering a Khutbah and said: "O Messenger of Allah, a stranger (meaning himself) has come to inquire about his Deen. He is quite ignorant about his Deen." Messenger of Allah (ﷺ) interrupted his Khutbah and turned to me. Then a chair was brought for him and he sat on it. He started instructing me what Allah had taught him. Then he resumed his Khutbah and completed it.[Muslim].
Arabic/English book reference: Book 1, Hadith 607