Bukhari Collection: ::Book Number 5:: Hadith # 644
Narrated Abu `Uthman:Allah's Apostle sent `Amr bin Al As as the commander of the troops of Dhat-us-Salasil. `Amr bin Al-`As said, "(On my return) I came to the Prophet and said, 'Which people do you love most?' He replied, `Aisha.' I said, 'From amongst the men?' He replied, 'Her father (Abu Bakr)'. I said, 'Whom (do you love) next?' He replied, "`Umar.' Then he counted the names of many men, and I became silent for fear that he might regard me as the last of them."