Musnad Ahmad 27:1936

Rawh and Hasan ibn Musa narrated to us, they said: Hammad ibn Zayd narrated to us, al-Zubayr ibn Arabi narrated to us, he said: A man asked Ibn Umar about touching the Black Stone. Hasan said: From al-Zubayr ibn Arabi, he said: I heard a man ask Ibn Umar about the Stone. He said: "I saw the Messenger of Allah, may Allah bless him and grant him peace, touch it and kiss it." A man said: "What do you think if I am crowded?" Ibn Umar said: "Put 'what do you think' in Yemen! I saw the Messenger of Allah, may Allah bless him and grant him peace, touch it and kiss it."