Musnad Abu Ya'la al-Mawsili 1:7

Abu Khaythama narrated to us, Ya'qub ibn Ibrahim informed us, my father informed us, from Salih, from Ibn Shihab, Salim ibn Abdullah informed us that he heard Abdullah ibn Umar ibn al-Khattab when Hafsa bint Umar became a widow from Khunays ibn Hudhafa al-Sahmi, and he was one of the companions of the Messenger of Allah, may Allah bless him and grant him peace. Umar said: I came to Uthman ibn Affan and offered him Hafsa bint Umar. I said: If you wish, I will marry Hafsa to you. He said: I will look into my affair. I waited for some nights, then he met me and said: It has appeared to me that I should not marry this day of mine. Umar said: Then I met Abu Bakr al-Siddiq and said to him: If you wish, I will marry Hafsa bint Umar to you. Abu Bakr remained silent and did not return anything to me. I was more upset with him than I was with Uthman. I waited for some days, then the Messenger of Allah, may Allah bless him and grant him peace, proposed to her, and I married her to him. Then Abu Bakr met me and said: Perhaps you were upset with me when you offered Hafsa to me and I did not return anything to you? I said: Yes. He said: Nothing prevented me from returning to you regarding what you offered me except that I knew that the Messenger of Allah, may Allah bless him and grant him peace, had mentioned her, and I would not disclose the secret of the Messenger of Allah, may Allah bless him and grant him peace. And had the Messenger of Allah, may Allah bless him and grant him peace, left her, I would have accepted her.