Musnad Ahmad 2:145

'Abd al-Razzaq narrated to us, 'Abd Allah ibn 'Umar narrated to us, from Nafi', from Ibn 'Umar: That 'Umar kissed the Stone, then said: "I know that you are a stone, and were it not that I saw the Messenger of Allah, may Allah bless him and grant him peace, kiss you, I would not have kissed you."