Musnad Ahmad 1153:1445

'Abd al-Rahman narrated to us, Sulaym ibn Hayyan narrated to us, from Sa'id ibn Mina, who said: I heard Ibn al-Zubayr saying: My maternal aunt 'A'ishah narrated to me that the Messenger of Allah (may Allah bless him and grant him peace) said to her: "Were it not that your people are newly removed from polytheism, or from the Age of Ignorance, I would have demolished the Ka'bah and leveled it to the ground. I would have made two doors for it: an eastern door and a western door. And I would have added six cubits to it from the Hijr, for the Quraysh shortened it when they built the Ka'bah."