Narrated Ibn 'Umar:
that the Prophet (ﷺ) said: "There are seven gates of Jahannam: Among them a gate for whoever carries a sword against my Ummah." Or he said: "Against the Ummah of Muhammad." (ID)
English reference (ID): Vol. 5, Book 44, Hadith 3123 (ID)
Arabic reference (ID): Book 47, Hadith 3414 (ID)