(7) باب مَنْ حَلَفَ بِمِلَّةٍ سِوَى مِلَّةِ الإِسْلاَمِ
Narrated Thabit bin Ad-Dahhak:
The Prophet (ﷺ) said, "Whoever swears by a religion other than Islam, is, as he says; and whoever commits suicide with something, will be punished with the same thing in the (Hell) Fire; and cursing a believer is like murdering him; and whoever accuses a believer of disbelief, then it is as if he had killed him."
Reference: Sahih al-Bukhari 6652
In-book reference: Book 83, Hadith 31
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 8, Book 78, Hadith 647