´It was narrated Abbas bin Rabiah said:` "I saw Umar coming to the Stone and saying: 'I know that you are just a stone; had I not seen the Messenger of Allah kiss you I would not have kissed you.' Then he came close to it and kissed it."
Hadith ReferenceSunan an-Nasa'i / The Book of Hajj / Hadith: 2940
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:متفق عليه