Sahih al-Bukhari 1610
صحيح البخاري#1610SahihNarrated Zaid bin Aslam that his father said:"I saw `Umar bin Al-Khattab kissing the Black Stone and he then said, (to it) 'Had I not seen Allah's Apostle kissing you, (stone) I would not have kissed you
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 25:96