It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that he said: When the Messenger of Allah (peace and blessings be upon him) set out for Tabuk, people began to lag behind. The Companions would say: "O Messenger of Allah! So-and-so has stayed behind." He (peace and blessings be upon him) would say: "Leave him. If there is any good in him, Allah will bring him to join you; and if it is otherwise, Allah has relieved you of him." Until it was said: "O Messenger of Allah! Abu Dharr has stayed behind; his camel has slowed him down." The Messenger of Allah (peace and blessings be upon him) said: "Leave him. If there is any good in him, Allah will bring him to join you; and if it is otherwise, Allah has relieved you of him." Meanwhile Sayyiduna Abu Dharr (may Allah be pleased with him) waited a little for his camel, but it remained slow. When he was getting delayed, he took up his belongings, loaded them on his back and set off on foot following the Messenger of Allah (peace and blessings be upon him). The Messenger of Allah (peace and blessings be upon him) had halted at a certain place when an onlooker saw him and said: "O Messenger of Allah! Here is a man walking along the road." The Messenger of Allah (peace and blessings be upon him) said: "Would that it were Abu Dharr!" When the people looked carefully, they exclaimed: "O Messenger of Allah! By Allah, it is indeed Abu Dharr!" Then the Messenger of Allah (peace and blessings be upon him) said: "May Allah have mercy on Abu Dharr. He walks alone, he will die alone, and he will be raised alone." Then time passed, and Sayyiduna Abu Dharr (may Allah be pleased with him) was moved to al-Rabadhah. When his death approached, he instructed his wife and his slave: "When I die, wash me, shroud me, then carry me and place me at the edge of the highway, and say to the first caravan that passes by you: 'This is Abu Dharr.'" When he died, they did so. Suddenly a caravan appeared, and they did not notice until their mounts had nearly reached the bier. In that caravan, with a group of the people of Kufah, was Sayyiduna Ibn Mas'ud (may Allah be pleased with him). They asked: "What is this?" They were told that it was the funeral of Abu Dharr. At this Sayyiduna Ibn Mas'ud (may Allah be pleased with him) burst into tears and said: The Messenger of Allah (peace and blessings be upon him) spoke the truth: "May Allah have mercy on Abu Dharr. He walks alone, he will die alone, and he will be raised alone." Then he dismounted and took charge of his burial himself until he had buried him. When they reached Madinah, the words of Sayyiduna Abdullah bin Mas'ud and his burial (of Abu Dharr) were mentioned before the Commander of the Believers Uthman (may Allah be pleased with him). This hadith has an authentic (sahih) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.