(55) باب قَضَاءِ الصَّلاَةِ الْفَائِتَةِ وَاسْتِحْبَابِ تَعْجِيلِ قَضَائِهَا
Abu Qatada reported that when the Messenger of Allah (ﷺ) was in a journey he got down for rest at night, and he used to lie down on his right side, and when he lay down for rest before the dawn, he used to stretch his forearm and place his head over his palm.
Reference: Sahih Muslim 683
In-book reference: Book 5, Hadith 401
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1453