Sayyiduna Anas bin Malik (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) prayed the dawn prayer while it was still dark, then he (peace and blessings be upon him) mounted and said: "Allahu akbar, kharibat Khaybar, inna idha nazalna bi-sahati qawmin fa-sa'a sabahu al-mundharin (Allah is the Greatest! Khaybar is ruined. When we descend upon the courtyard of a people, evil is the morning of those who were warned)." The people came out, moving through the lanes and saying: "Muhammad and his army!" Hammad said: Khamis means the army. He (peace and blessings be upon him) overcame them, killed the fighting men and took the children captive. Sayyidah Safiyyah (may Allah be pleased with her) fell to the share of Sayyiduna Dihyah al-Kalbi (may Allah be pleased with him); then she was given to the share of the Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) married her and made her freedom her dowry (mahr). Abd al-Aziz (may Allah have mercy on him) asked Thabit (may Allah have mercy on him): "Did you ask Sayyiduna Anas (may Allah be pleased with him) what he (peace and blessings be upon him) gave her as dowry?" He said: "He (peace and blessings be upon him) made her dowry the freedom of her own person." And he smiled.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17979