1110.`Aishah (May Allah be pleased with her) reported: When the Prophet (PBUH) had performed two Rak`ah before the Fajr prayer, he would lie down on his right side.
[Al-Bukhari].

1111. `Aishah (May Allah be pleased with her) reported: When the Prophet (PBUH) finished the `Isha prayer, he would perform eleven Rak`ah before the Fajr prayer, concluding each two Rak`ah with Taslim (i.e., saying As-Salamu `Alaikum) and observing the Witr (odd) at the end. When the Mu'adhdhin finished proclaiming Adhan for the Fajr prayer and it was dawn, he would rise and perform two short Rak`ah, and then would lie down on his right side till the Mu'adhdhin came to (inform) him about Iqamah.
[Muslim].

1112. Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah (PBUH) said, "When anyone of you has performed two of Sunnah before the Fajr prayer, he should lie down on his right side."
[Abu Dawud and At-Tirmidhi].

Commentary: The preceding Ahadith described the practice of the Prophet (PBUH) while the present one tells us about his order that one should lie down on his right side after offering the two Sunnah of Fajr prayer. Thus, this practice is proved by his speech as well as action which does not leave any doubt about it being a Sunnah and Mustahabb (desirable).