Shama-il Tirmidhi Chapter 38, Hadith Number 3 (244).

‘Aayeshah Radiyallahu ‘Anha narrates: “Every night before Rasulullah Sallallahu ‘Alayhi Wasallam slept on his bed, he put together his hands (as in the du’aa) and blew on it and recited (the surahs of) AI-Ikhlaas (Qul huwauahu ahad), AI-Falaq (Qul a’udhu birabbil falaq), and An-Naas (Qui a’udhu birabbin naas) and wiped those parts of the body that he could (wherever the hand could reach). He began with the head, then the face and then the front part of his body. This was done thrice”.

Commentary
The ahaadith state that Sayyidina Rasulullah Sallallahu ‘Alayhi Wasallam recited different du’aas before he went to bed. He also recited different surahs and aayaat of the Qur-aan. It is reported from Sayyidina Rasulullah Sallallahu ‘Alayhi Wasallam that if one recites a portion of the Qur-aan before sleeping, an angel is appointed to protect one till one awakens. From the above hadith it is found that Sayyidina Rasulullah Sallallahu ‘Alayhi Wasallam himself recited the three surahs mentioned. Besides these, it has been narrated that he recited the musabbihaat. i.e. those surahs that begin with Sabbaha, Yusabbibu, Subhaana etc. He also regularly recited the Surahs of (Alif Laam) Sajdah and Surah Mulk (Tabaarak). The ahaadith state that he also recited the Aayatul Kursi and the last two aayahs of Suratul Baqarah. A sahabi reports that, Sayidina Rasulullah Sallallahu ‘Alayhi Wasallam Advised him to recite Suratul Kaafirun (Qul yaa ayyuhal kaafirun) before retiring to bed. Besides these, other du’aas have been narrated that were read by Sayyidina Rasulullah Sallallahu ‘Alayhi Wasallam before sleeping. – Fathul Baari.