Sahih Bukhari Volume 9, Book 92, Hadith Number 459.

Narrated By Jubair bin Mutim : A lady came to Allah’s Apostle and she talked to him about something, and he gave her some order. She said, “O Allah’s Apostle! If I should not find you?” He said, “If you should not find me, then go to Abu Bakr.” Ibrahim bin Sa’d said, “As if she meant the death (of the Prophet).”