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 states that he heard the Prophet, may Allah bless him and grant him peace, say, "A person who knowingly claims a father other than his own has disbelieved. A person who claims to be from a people when he is not one of them will take his place in the Fire. A person who calls a man an unbeliever or says, 'Enemy of Allah,' when that is not the case will have that come back on him."