ENOfficial
Abu Huraira said that God’s Messenger forbade trailing garments during prayer and that a man should cover his mouth. Abu Dawud and Tirmidhi transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: نَهَى عَنِ السَّدْلِ فِي الصَّلَاةِ وَأَنْ يُغَطِّيَ الرَّجُلُ فَاهُ. رَوَاهُ أَبُو دَاوُدَ وَالتِّرْمِذِيُّ
sunnah.com