Sayyiduna Abu Dharr (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "O Abu Dharr!" I said: Here I am, at your service. He (peace and blessings be upon him) said: "How will you be when death strikes the people (so widely) that a house, meaning the grave, will be (exchanged) for a slave?" I said: Allah and His Messenger (peace and blessings be upon him) know best, or (I said:) whatever Allah and His Messenger (peace and blessings be upon him) choose (for me). He (peace and blessings be upon him) said: "Hold fast to patience."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السرقة / 17238