It wasnarrated that 'Abdullah bin Sarjis said:
"I saw the baldforeheadof 'Umar bin Khattab when he kissed the Black Stone and said:'Iam kissing you, although I know that you are only a stone and youcanneither cause harm nor bring benefit. Had I not seen the MessengerofAllah (ﷺ) kissing you, I would not have kissed you.'" (PT)
English reference (PT): Vol. 4, Book 25, Hadith 2943 (PT)
Arabic reference (PT): Book 25, Hadith 3056 (PT)