Ibn Abu Mulaika reported:
I heard A'isha as saying and she was asked as to whom Allah's Messenger (ﷺ) would have nominated his successor if he had to nominate one at all. She said: Abu Bakr. It was said to her: Then whom after Abu Bakr? She said: Umar. It was said to her. Then whom after 'Umar? She said: Abu Ubaida b. Jarrab, and then she kept quiet at this.