The last ten days of Ramadan are very precious indeed:

Allah's Messenger used to exert himself in devotion during the last ten nights to a greater extent than at any other time. (saheeh muslim).

Hazrat Aishah (RA) reported that during the last ten days of Ramadan; the Messenger of Allah would wake his wives up during the night and then remain apart from them (that is, being busy in acts of worship)- (Bukhaari)

Hazrat Aishah (RA) also reports that with the start of the last ten days of Ramadan, the Prophet (SAW) 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 (Bukhaari)