ENOfficial
Abu Huraira reported: Abu'l-Qasim (the kunya of Allah's Messenger, 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).
Source: sunnah.com
Other translations
Arabic
حَدَّثَنِي عَمْرٌو النَّاقِدُ، وَابْنُ أَبِي عُمَرَ، قَالَ عَمْرٌو حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ أَيُّوبَ، عَنِ ابْنِ سِيرِينَ، سَمِعْتُ أَبَا هُرَيْرَةَ، يَقُولُ قَالَ أَبُو الْقَاسِمِ صلى الله عليه وسلم " مَنْ أَشَارَ إِلَى أَخِيهِ بِحَدِيدَةٍ فَإِنَّ الْمَلاَئِكَةَ تَلْعَنُهُ حَتَّى وَإِنْ كَانَ أَخَاهُ لأَبِيهِ وَأُمِّهِ " .
sunnah.com