Sayyidah Aishah (may Allah be pleased with her) said: When (Sayyiduna) Abu Bakr (may Allah be pleased with him) became gravely ill, so-and-so and so-and-so came to him and said: O successor of the Messenger of Allah (peace and blessings be upon him)! What will you say to your Lord tomorrow when you come before Him, having appointed Umar (may Allah be pleased with him) as successor over us? She said: We sat him up, and he said: Are you trying to frighten me with Allah? I will say: I appointed over them the best of them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قتال أهل البغي / 16575