Abu Dharr (May Allah be pleased with him) reported:
I stepped out one night and saw Messenger of Allah (ﷺ) walking by himself. I began to walk in the moonlit night. He turned round and saw me and asked, "Who is there?" I replied: "Abu Dharr."[Al-Bukhari and Muslim].
App reference: Book 6, Hadith 31
Arabic/English book reference: Book 6, Hadith 875