عنِ ابنِ مَسعودٍ رضي اللَّهُ عَنهُ قال: قال رسُولُ اللَّهِ صَلّى اللّهُ عَلَيْهِ وسَلَّم: «سِباب المُسْلِمِ فُسوقٌ، وقِتَالُهُ كُفْرٌ» متفقٌ عليه.
Ibn Mas'ud (may Allah be pleased with him) reported that the Messenger of Allah (peace and blessings be upon him) said: "Reviling a Muslim is iniquity (fusuq), and fighting him is disbelief (kufr)." Agreed upon (al-Bukhari and Muslim).
الشرح · explanation
سباب المسلم: أي شتمه والتكلم في عرضه بما يعيبه. فسوق: خروج عن طاعة اللّه تعالى. قتاله كفر: أي قتله كالكفر في الإثم والتحريم، ويجوز أن يراد من المقاتلة المشادة والمدافعة.
"Reviling a Muslim": that is, insulting him and speaking of his honor with what disgraces him. "iniquity" (fusuq): departing from obedience to Allah the Exalted. "fighting him is disbelief": that is, killing him is like disbelief in its sinfulness and prohibition; it may also be that what is meant by fighting is quarreling and shoving.
الدروس · lessons
الزجر من لعن المسلم وقتاله، لما في ذلك من كفران النعمة وعدم أداء حق أخوة الإيمان.
A stern warning against cursing a Muslim or fighting him, because of the ingratitude for blessings and the failure to fulfill the right of the brotherhood of faith that this entails.