Musnad Ahmad 1153:2343

Ya'qub narrated to us, he said: My father narrated to us, from Ibn Ishaq, he said: Yahya ibn 'Abbad ibn 'Abdullah ibn al-Zubayr narrated to me, from his father, 'Abbad, from 'A'ishah, the wife of the Prophet, may Allah bless him and grant him peace, she said: When the people of Makkah sent for the ransom of their captives, Zaynab, the daughter of the Messenger of Allah, may Allah bless him and grant him peace, sent for the ransom of Abu al-'As ibn al-Rabi' with wealth. She also sent with it a necklace of hers that had belonged to Khadijah, which she had entered with to Abu al-'As when he consummated the marriage with her. She said: When the Messenger of Allah, may Allah bless him and grant him peace, saw it, he felt a severe tenderness for her and said: "If you see fit to release her captive for her and return to her what is hers, then do so." They said: "Yes, O Messenger of Allah." So they released him and returned to her what was hers.