Sahih Bukhari Volume 3, Book 47, Hadith Number 803.

Narated By Abu Huraira : Allah’s Apostle said, “The Prophet Abraham migrated with Sarah. The people (of the town where they migrated) gave her Ajar (i.e. Hajar). Sarah returned and said to Abraham, “Do you know that Allah has humiliated that pagan and he has given a slave-girl for my service?”