Sahih Bukhari

Narrated `Abdul `Aziz bin Suhaib:Anas bin Malik said, ""The Prophet (ﷺ) took Safiya as a captive. He manumitted her and married her."" Thabit asked Anas, ""What did he give her as Mahr (i.e. marriage gift)?"" Anas replied. ""Her Mahr was herself, for he manumitted her