وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ الْمُجَبَّرِ، أَنَّهُ كَانَ يَرَى سَالِمَ بْنَ عَبْدِ اللَّهِ إِذَا رَأَى الإِنْسَانَ يُغَطِّي فَاهُ وَهُوَ يُصَلِّي جَبَذَ الثَّوْبَ عَنْ فِيهِ جَبْذًا شَدِيدًا حَتَّى يَنْزِعَهُ عَنْ فِيهِ ‏.‏

Yahya related to me from Malik from Abd ar-Rahman ibn al-Mujabbarthat he used to see Salim ibn Abdullah pull the cloth away fiercelyfrom the mouth of any man he saw covering his mouth while praying. Translation Not Available

Book Ref: Muwatta Imam Malik Book 1 Hadith 31
Web Ref:  Muwatta Imam Malik Book 1 Hadith 31

---