Abu'l-Qasim (the kunya of Messenger of Allah, may peace be upon him), said: He who pointed a weapon towards his brother the angels invoke curse upon him even if he is his real brother so long as he does not abandon it (the pointing of weapon towards one's brother Muslim).  

أَبُو الْقَاسِمِ ﷺ مَنْ أَشَارَ إِلَى أَخِيهِ بِحَدِيدَةٍ فَإِنَّ الْمَلاَئِكَةَ تَلْعَنُهُ حَتَّى وَإِنْ كَانَ أَخَاهُ لأَبِيهِ وَأُمِّهِ  

Abu Huraira reported a hadith like this from Allah's Apostle ﷺ through another chain of transmitters.  

عَنِ النَّبِيِّ ﷺ بِمِثْلِهِ  

None amongst you should point a weapon towards his brother, for he does not know that Satan might cause the weapon (to slip) from his hand and (he may injure anyone) and thus he may fall into Hell-Fire.  

عَنْ رَسُولِ اللَّهِ ﷺ فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ رَسُولُ اللَّهِ ﷺ لاَ يُشِيرُ أَحَدُكُمْ إِلَى أَخِيهِ بِالسِّلاَحِ فَإِنَّهُ لاَ يَدْرِي أَحَدُكُمْ لَعَلَّ الشَّيْطَانَ يَنْزِعُ فِي يَدِهِ فَيَقَعُ فِي حُفْرَةٍ مِنَ النَّارِ