Musnad Abu Ya'la al-Mawsili 150:228

'Abd al-A'la narrated to us, Wahib narrated to us, Sa'id Abu Mas'ud al-Jurayri narrated to us, from 'Abdullah ibn Shaqiq, who said: I said to 'A'ishah, "O Mother of the Believers, which of the Companions of the Messenger of Allah, may Allah bless him and grant him peace, was most beloved to him?" She said, "Abu Bakr." I said, "Then who?" She said, "Then 'Umar." He said, "I said, 'Then who?'" She said, "Then Abu 'Ubaydah ibn al-Jarrah." He said, "I said, 'Then who?'" He said, "So she remained silent."