´Abbas bin Rabi'ah said:` "I saw Umar bin Al-Khattab kissing the (Black) Stone and saying: 'I am kissing you while I know that you are just a stone, and if I had not seen the Messenger of Allah kissing you, I would not kiss you.'"
Hadith Referenceسنن ترمذي / كتاب الحج عن رسول الله صلى الله عليه وسلم / 860
´Az-Zubair bin Arabi narrated:` That a man asked Ibn Umar about touching the (Black) Stone, so he said: "I saw the Prophet touching it and kissing it." So the man said: "What is your view if there is a throng (around the Ka'bah) and what is your view if the people overpowered me?" Ibn Umar said: "Leave 'What is your view' in Yemen. I saw the Prophet touching it and kissing it."
Hadith Referenceسنن ترمذي / كتاب الحج عن رسول الله صلى الله عليه وسلم / 861