ثُمَّ إيَّاكُمْ وَتَهْزِيعَ الاْخْلاَقِ وَتَصْرِيفَهَا، وَاجْعَلُوا اللِّسَانَ وَاحِداً، وَلْيَخْتَزِنَ الرَّجُلُ لِسَانَهُ، فَإنَّ هذَا اللِّسَانَ جَمُوحٌ بِصَاحِبِهِ، وَاللهِ مَا أَرَى عَبْداً يَتَّقِي تَقْوَى تَنْفَعُهُ حَتَّى يَخْتَزِنَ لِسَانَهُ، وَإنَّ لِسَانَ الْمُؤْمِنِ مِنْ وَرَاءِ قَلْبِهِ، وَإنَّ قَلْبَ الْمُنَافِقِ مِنْ وَرَاءِ لِسَانِهِ: لاِنَّ الْمُؤْمِنَ إذَا أَرَادَ أَنْ يَتَكَلَّمَ بَكَلاَم تَدَبَّرَهُ فِي نَفْسِهِ، فَإنْ كَانَ خَيْراً أَبْدَاهُ، وَإنْ كَانَ شَرّاً وَارَاهُ، وَإنَّ الْمُنَافِقَ يَتَكَلَّمُ بِمَا أَتَى عَلَى لِسَانِهِ لاَ يَدْرِي مَاذَا لَهُ، وَمَاذَا عَلَيْهِ،
Beware from destroying your manners and changing them, maintain one tongue. A man should control his tongue because the tongue is obstinate with its master. By Allāh, I do not find that fear of Allāh benefits a man who practises it unless he controls his tongue. Certainly the tongue of a believer is at the back of his heart while the heart of a hypocrite is at the back of his tongue; because, when a believer intends to say anything, he thinks it over in his mind. If it is good he discloses it, but if it is bad he lets it remain concealed. While a hypocrite speaks whatever comes to his tongue, without knowing what is in his favour and what goes against him.