Sahih Bukhari
Funerals (Al-Janaaiz)
Volume: 002 / Book Number: 023 / Hadith Number: 350
Narrated Hafsa bint Sirin:
Um 'Atiyya said that they had entwined the hair of the daughter of Allah's Apostle in three braids. They first undid her hair, washed and then entwined it in three braids."