Silsilat al-Ahadith al-Sahihah

The meaning is stated: When Sayyiduna Uthman bin Maz'oon (may Allah be pleased with him) passed away, after the burial was completed, the Noble Prophet (peace and blessings be upon him) ordered a man to bring a stone, but he could not lift it. Seeing this, the Prophet (peace and blessings be upon him) himself stood up, removed the cloth from his arms. The companion of the Messenger says: It is as if I am (even now) looking at the whiteness of the Prophet’s (peace and blessings be upon him) arms. The Prophet (peace and blessings be upon him) lifted that stone and placed it at the head side of the grave and said: “This stone is a sign for my brother’s grave. I will bury members of my family beside it.”