Sayyiduna Umar (may Allah be pleased with him) came to the Black Stone, kissed it and said: "I know that you are a stone; you can neither benefit nor harm. Had I not seen the Messenger of Allah (peace and blessings be upon him) kissing you, I would not have kissed you."
(b) In the narration of Ya'la (bin Ubayd) the wording is: I saw Sayyiduna Umar (may Allah be pleased with him) face the Black Stone, then he said: "By Allah, I know that you are a stone. Had I not seen the Messenger of Allah (peace and blessings be upon him) kissing you, I would not have kissed you." Then he went forward and kissed it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9219
Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) used to kiss the Black Stone and say: "I surely know that you are a stone; you neither harm nor benefit. But I saw Abu al-Qasim (peace and blessings be upon him) showing great care for you."
(b) In another narration: Sayyiduna Umar (may Allah be pleased with him) kissed the Black Stone and said: "I am kissing you, and I surely know that you are a stone," then he mentioned the rest of the narration.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9220
Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) said: We entered Makkah when the forenoon was well advanced. The Prophet (peace and blessings be upon him) came to the door of the mosque and made his camel kneel, then entered the mosque and began with the Black Stone, touching it, and his eyes (peace and blessings be upon him) overflowed with tears. Then he (peace and blessings be upon him) jogged three circuits and walked four, until, when he had finished, he kissed the Black Stone, placed his hands on it and wiped his face with them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9221
A man asked Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) about touching the Black Stone. He said: "The Prophet (peace and blessings be upon him) used to touch it and kiss it." The man said: "What do you think if there is a crowd and I am overpowered?" He said: "Leave this 'what do you think' in Yemen. I saw the Prophet (peace and blessings be upon him) touching it and kissing it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9222