كتاب الأيمان والنذور
Read the English translation first, with the original Arabic directly underneath.
Thabit bin Ad-Dahhak narrated that the Messenger of Allah said:
"Whoever swears by a religion other than Islam, telling a lie, will be as he said, and whoever kills himself with something will be punished with it in the Hereafter."
مَنْ حَلَفَ بِمِلَّةٍ سِوَى الإِسْلاَمِ كَاذِبًا فَهُوَ كَمَا قَالَ وَمَنْ قَتَلَ نَفْسَهُ بِشَىْءٍ عُذِّبَ بِهِ فِي الآخِرَةِ