Umar kissed the Black Stone and then said, "I know well that you are only a stone, and had I not seen the Messenger of Allah ﷺ kiss you, I would not have kissed you."
حدثنا عبد الرزاق حدثنا عبد الله بن عمر عن نافع
أن عمر رضي الله عنه قبل الحجر ثم قال قد علمت أنك حجر ولولا أني رأيت رسول الله ﷺ قبلك ما قبلتك
Its isnad is sahih. Abdullah bin Umar bin Hafs bin Asim bin Umar bin Khattab is trustworthy, though there is something questionable about his memory. The hadith is a repeat of 176. See also 190.