307. hadíth
وَقَالَ رَسُولُ اَللَّهِ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ: «لاَ يُطَوِّلَنَّ أَحَدُكُمْ شَارِبَهُ فَإِنَّ اَلشَّيْطَانَ يَتَّخِذُهُ مِجَنّاً يَسْتَتِرُ بِهِ.
The Messenger of Allah (saws) said: "None of you should allow their moustache grow long, for Shaytan uses it as a shield to conceal himself”.