I saw Tawsa passing by the Corner. If he found a crowd around it, he would pass by without pushing through. If he found it empty, he would kiss it three times. Then he said, "I saw Ibn Abbas do the same."Ibn Abbas said, "I saw Umar bin Khattab do the same. Then Umar said, 'You are only a stone that can neither benefit nor harm. Were it not that I saw the Messenger of Allah ﷺ kiss you, I would not kiss you.' Then Umar said, 'I saw the Messenger of Allah ﷺ do the same.'"
أخبرنا عمرو بن عثمان قال حدثنا الوليد
رأيت طاوسا يمر بالركن فإن وجد عليه زحاما مر ولم يزاحم وإن رآه خاليا قبله ثلاثا ثم قال رأيت ابن عباس فعل مثل ذلك وقال ابن عباس رأيت عمر بن الخطاب فعل مثل ذلك ثم قال إنك حجر لا تنفع ولا تضر ولولا أني رأيت رسول الله ﷺ قبلك ما قبلتك ثم قال عمر رأيت رسول الله ﷺ فعل مثل ذلك
[Its isnad is sahih] Bazzar narrated it in Bahr Zakhkhar, 1/324–325, no. 208, from the hadith of Walid bin Muslim, with the same wording, and he stated clearly that he heard it directly there. The hadith is also in the Kubra, no. 3922.