Sahih Bukhari
Praying at Night in Ramadaan (Taraweeh)
Volume: 003 / Book Number: 032 / Hadith Number: 241
Narrated Aisha:
With the start of the last ten days of Ramadan, the Prophet used to tighten his waist belt (i.e. work hard) and used to pray all the night, and used to keep his family awake for the prayers.