Hadith 10:131
He said that God’s Messenger set Safiya free and married her, making her freedom her dower, and he held a wedding-feast for her with hais (A dish made of dates mixed with clarified butter and dried curd, kneaded and rubbed together. Sometimes flour was added.) (Bukhari and Muslim.)
وَعَنْهُ قَالَ: إِنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ أَعْتَقَ صَفِيَّةَ وَتَزَوَّجَهَا وَجَعَلَ عِتْقَهَا صَدَاقَهَا وَأَوْلَمَ عَلَيْهَا بحيس. مُتَّفق عَلَيْهِ
Original Reference: Mishkat al-Masabih 3213