Sahih Bukhari Volume 007, Book 072, Hadith Number 851.
Narrated By Anas bin Malik : We were coming from Khaibar along with Allah's Apostle while l was riding behind Abu Talha and he was proceeding. While one of the wives of Allah's Apostle was riding behind Allah's Apostle, suddenly the foot of the camel Slipped and I said, "The woman!" and alighted (hurriedly). Allah's Apostle said, "She is your mother." So l resaddled the she-camel and Allah's Apostle mounted it. When he approached or saw Medina, he said, "Ayibun, ta'ibun, 'abidun, li-Rabbina hami-dun."