حَدَّثَنَا إِبْرَاهِيمُ بْنُ مُوسَى قَالَ‏:‏ أَخْبَرَنِي يَحْيَى بْنُ زَكَرِيَّا بْنِ أَبِي زَائِدَةَ، عَنْ زَكَرِيَّا، عَنْ أَبِي إِسْحَاقَ، عَنْ مُحَمَّدِ بْنِ سَعْدِ بْنِ مَالِكٍ، عَنْ أَبِيهِ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ‏:‏ سِبَابُ الْمُسْلِمِ فُسُوقٌ‏.‏

Abu Dharr is reported as saying that he heard the Prophet, may Allah bless him and grant him peace, say, "If a man accuses another man of deviance or accuses him of disbelief, that accusation will come back on him if his companion is not as he said."