Sahih Bukhari Volume 4, Book 61, Hadith 3641

حَدَّثَنا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا مُعَاذٌ، قَالَ حَدَّثَنِي أَبِي، عَنْ قَتَادَةَ، حَدَّثَنَا أَنَسٌ ـ رضى الله عنه ـ أَنَّ رَجُلَيْنِ، مِنْ أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم خَرَجَا مِنْ عِنْدِ النَّبِيِّ صلى الله عليه وسلم فِي لَيْلَةٍ مُظْلِمَةٍ وَمَعَهُمَا مِثْلُ الْمِصْبَاحَيْنِ، يُضِيآنِ بَيْنَ أَيْدِيهِمَا، فَلَمَّا افْتَرَقَا صَارَ مَعَ كُلِّ وَاحِدٍ مِنْهُمَا وَاحِدٌ حَتَّى أَتَى أَهْلَهُ‏

Narrated By Anas : Once two men from the companions of Allah's Apostle went out of the house of the Prophet on a very dark night. They were accompanied by two things that resembled two lamps lighting the way in front of them, and when they parted, each of them was accompanied by one of those two things (lamps) till they reached their homes.