Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
Bukhari :: Book 6 :: Volume 60 :: Hadith 436
Narrated Ibn Abbas:
I intended to ask 'Umar so I said, "Who were those two ladies who tried to back each other against the Prophet?" I hardly finished my speech when he said, They were 'Aisha and Hafsa."