عَنْ ثَابِتِ بْنِ الضَّحَّاكِ الْأَنْصَارِيِّ رَضِيَ اللَّهُ عَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَ ((لَعْنُ الْمُؤْمِنِ كَقَتْلِهِ))
It is narrated from Sayyiduna Thabit bin Dhahak Ansari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Cursing a believer is equivalent to killing him.