رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 1111
The Book of Virtues
Desirability of Lying down on one's right side after the Sunnah of Fajr Prayer
وَعَنْهَا قَالَتْ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُصَلِّي فِيمَا بَيْنَ أَنْ يَفْرُغَ مِنْ صَلاَةِ الْعِشَاءِ إِلَى الْفَجْرِ إِحْدَى عَشْرَةَ رَكْعَةً يُسَلِّمُ بَيْنَ كُلِّ رَكْعَتَيْنِ، وَيُوتِرُ بِوَاحِدَةٍ، فَإِذَا سَكَتَ الْمُؤَذِّنُ مِنْ صَلاَةِ الْفَجْرِ، وَتَبَيَّنَ لَهُ الْفَجْرُ وجاء الْمُؤَذِّنُ، قَامَ فَرَكَعَ رَكْعَتَيْنِ خَفِيفَتَيْنِ، ثُمَّ اضْطَجَعَ عَلَى شِقِّهِ الأَيْمَنِ هكذا حَتَّى يَأْتِيَهُ الْمُؤَذِّنُ لِلإِقَامَةِ". ((رَوَاهُ مُسْلِم)). (15)
'Aishah (May Allah be pleased with her) reported: When the Prophet (ﷺ) 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].
Riyad as-Salihin, 1111