Volume 2 · Book 26 · Hadith 679
Narrated 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.' "
— Sahih Bukhari, Volume 2, Book 26: Pilgrimmage (Hajj), Hadith #679
