'Who should I call to settle this matter?'

Aishah, the mother of the faithful, related the following:
 
Once in an effort to settle an argument between the Prophet (p.b.u.h) and I, the Prophet (p.b.u.h) asked, “Who should I call to settle this matter? Would you like Abu Ubaydah?”.  To this I replied, “No, he is soft and lenient and would judge in your favor.” "What about Umar b. al-Khattab?" inquired the Prophet (p.b.u.h). To this I replied, “I fear Umar.” Finally, he asked, “Would you like Abu Bakr [my father]?” I instantly agreed.
 
Accordingly, he sent someone to call my father and when he came, the Prophet (p.b.u.h) told him, “I want you to arbitrate this matter between Aishah and me.” Surprised, my father exclaimed, “I, O Messenger of Allah?” “Yes, you” the Prophet (p.b.u.h) replied. 
 
With that out of the way, the Messenger of Allah began to speak, I interrupted saying: “Be fair when you talk, O Messenger of Allah!” As soon as I said the words, my father stretched out his hand and slapped me saying, “Woe to you! Who would be fair, if not the Messenger of Allah?"
 
The Prophet (p.b.u.h) immediately came to my defence saying, “We didn’t come to you to settle the matter in this way! We will settle our dispute ourselves!”