Sayyiduna Ya'la bin Umayyah (may Allah be pleased with him) says that once I performed Tawaf with Sayyiduna Umar (may Allah be pleased with him). He performed Istilam of the Hajar Aswad. When I reached the Rukn Yamani, I took the hand of Sayyiduna Umar (may Allah be pleased with him) so that he could perform Istilam. Sayyiduna Umar (may Allah be pleased with him) said: What is the matter with you? I said: Will you not perform Istilam? He said: Have you never performed Tawaf with the Prophet (peace and blessings be upon him)? I said: Why not! He said: Did you see the Prophet (peace and blessings be upon him) perform Istilam of this? I said: No! He said: Is there not for you in the person of the Messenger of Allah (peace and blessings be upon him) a good example? I said: Why not. He said: Then leave it.