Urwa bin Zubayr reported,

Ayesha commented on the verse "Those who responded to Allah and the Messenger after injury had befallen them. For those among them who did good and were mindful of Allah there is a great reward" [Al Imran 3:172].She said to Urwa, "Son of my sister, your own two forefathers were among them, Zubayr and Abu Bakr. When the Messenger of Allah ﷺ suffered what he suffered on the day of Uhud and the polytheists had turned away from him, he feared that they would come back, so he asked, 'Who will go after them?' Seventy men from among them answered the call."The narrator said that Abu Bakr and Zubayr were among them.

حدثنا محمد حدثنا أبو معاوية

عن هشام عن أبيه

عن عائشة رضي الله عنها {الذين استجابوا لله والرسول من بعد ما أصابهم القرح للذين أحسنوا منهم واتقوا أجر عظيم} قالت لعروة يا ابن أختي كان أبواك منهم الزبير وأبو بكر لما أصاب رسول الله ﷺ ما أصاب يوم أحد وانصرف عنه المشركون خاف أن يرجعوا قال من يذهب في إثرهم فانتدب منهم سبعون رجلا قال كان فيهم أبو بكر والزبير