Al-Qasim bin Muhammad said that Sayyidah Aishah (may Allah be pleased with her) said: "Oh, my head!" The Messenger of Allah (peace and blessings be upon him) said: "If that were to happen to you (if you died) while I am alive, I would seek forgiveness for you and supplicate for you." Sayyidah Aishah (may Allah be pleased with her) said: "Oh, my loss! By Allah, I think you would like me to die; and if that happened, you would spend the end of that very day celebrating a wedding night with one of your wives." She said: The Messenger of Allah (peace and blessings be upon him) said: "Rather, it is my own head (that is in pain). I intended to send for Sayyiduna Abu Bakr and his son (may Allah be pleased with them both) and make a covenant (of succession), lest those who would speak should speak or those who would wish should wish. Then I said: Allah will refuse (anyone else) and the believers will reject (him); or (he said): Allah will reject and the believers will refuse."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6568