(a) Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) said to the Black Stone: I certainly know that you are a stone that can neither benefit nor harm, but I saw the Messenger of Allah (peace and blessings be upon him) touch you, so I do so as well. Then he touched it and said: We no longer have any need for ramal; we did it only to show the polytheists, and Allah has destroyed them. Then he said: It is something that the Messenger of Allah (peace and blessings be upon him) did, and we do not like to abandon it. Then he performed ramal.
(b) It is narrated from Ata bin Abi Rabah (may Allah have mercy on him) that the Messenger of Allah (peace and blessings be upon him), Sayyiduna Abu Bakr, Sayyiduna Umar, Sayyiduna Uthman (may Allah be pleased with them) and the caliphs after them performed ramal for three rounds and walked slowly for four rounds.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9277