عن ثابت بن الضحاك، عن الرسول صلى الله عليه وسلم قال: “من حلَفَ بملَّةٍ غيرِ الإسلامِ كاذِبًا فَهوَ كما قالَ ، ومن قتلَ نفسَه بشيءٍ عُذِّبَ بِه في نارِ جَهنَّمَ ، ولعْنُ المؤمنِ كقتلِهِ ، ومن رمى مؤمنًا بِكفرٍ فَهوَ كقتلِهِ” صحيح البخاري

Narrated Thabit bin Ad-Dahhak: The Prophet (ﷺ) said, “Whoever swears by a religion other than Islam (i.e. if he swears by saying that he is a non-Muslim in case he is telling a lie), then he is as he says if his oath is false 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.“ Sahih al-Bukhari 6105 In-book reference : Book 78, Hadith 132         USC-MSA web (English) reference : Vol. 8, Book 73, Hadith 126