Sayyiduna Anas (may Allah be pleased with him) said that Zahir bin Hizam, or Haram, was a man from the desert. The Prophet (peace and blessings be upon him) loved him very much, and he was a dark-complexioned man. One day the Prophet (peace and blessings be upon him) came while he was selling his goods, and he (peace and blessings be upon him) placed his hands over his eyes from behind, so that he could not see. He said: "Let me go! Who is this?" Then he tried to turn and look, and he recognised that it was the Prophet (peace and blessings be upon him). Having recognised him, he pressed his back against the chest of the Prophet (peace and blessings be upon him), while he (peace and blessings be upon him) was saying: "Who will buy this slave from me?" He said: O Messenger of Allah (peace and blessings be upon him), then you will find me very cheap. He (peace and blessings be upon him) said: "But you are not cheap with Allah; rather, with Allah you are precious."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 21172