Musnad Abu Ya'la al-Mawsili 150:383

Mujahid ibn Musa narrated to us, Abu Usamah narrated to us, al-Jurayri Abu Mas'ud narrated to us, from Abdullah ibn Shaqiq, who said: I said to Aisha, "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." I said, "Then who?" She said, "Then Abu Ubaydah ibn al-Jarrah." I said, "Then who?" He said: She remained silent.