ENOfficial
Abu Qatada told that when God's Messenger encamped at night on a journey he lay down on his right side, and when he encamped a little before morning he raised his forearm and placed his head on the palm of his hand. Muslim transmitted it.
Source: sunnah.com
Other translations
Arabic
عَن أبي قتادةَ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا كَانَ فِي سَفَرٍ فَعَرَّسَ بِلَيْلٍ اضْطَجَعَ عَلَى يَمِينِهِ وَإِذَا عَرَّسَ قُبَيْلَ الصُّبْحِ نَصَبَ ذِرَاعَهُ وَوَضَعَ رَأْسَهُ عَلَى كَفِّهِ. رَوَاهُ مُسلم
sunnah.com