Musnad Ahmad 1153:1030

Waki' narrated to us, Isma'il bin 'Abd al-Malik bin Abi al-Safira' narrated to us, from Ibn Abi Mulayka, from 'Aisha, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "If we had the capacity, I would have demolished the Ka'bah and rebuilt it, and I would have made two doors for it: a door through which people enter, and a door through which they exit." She said: When Ibn al-Zubayr took charge, he demolished it and made two doors for it. She said: It remained as such. Then, when al-Hajjaj overcame him, he demolished it and restored it to its original construction.