`A’ishah (may Allah be pleased with her) narrated that the Messenger of Allah (peace be upon him) used to strive more in worship during Ramadan than he strove in any other time of the year; and he would devote himself more (in the worship of Allah) in the last ten nights of Ramadan than he strove in earlier part of the month.” (Muslim)
In another hadith, `A’ishah (may Allah be pleased with her) said: “With the start of the last ten days of Ramadan, Messenger of Allah (peace be upon him) would pray all the night, and would keep his family awake for the prayers. He tied his lower garment (i.e., avoided sleeping with his wives) and devoted himself entirely to prayer and supplication.” (Agreed Upon)
When do the last 10 nights begin? Do the last 10 days mean the same thing? People do tend to get confused. Also regarding itikaf, when do people begin? When do the last 10 nights end? Watch this short video to get the answer with Sheikh Abu Eesa.