Sunan Ibn Majah, Book 11, Hadith 2176 (In-Book) ⓘ
It was narrated that Thabit bin Ad-Dahhak said: The Messenger of Allah said: 'Whoever takes an oath to follow a religion other than Islam, telling a deliberate lie, he will be as he said.'"
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنْ خَالِدٍ الْحَذَّاءِ، عَنْ أَبِي قِلاَبَةَ، عَنْ ثَابِتِ بْنِ الضَّحَّاكِ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ حَلَفَ بِمِلَّةٍ سِوَى الإِسْلاَمِ كَاذِبًا مُتَعَمِّدًا فَهُوَ كَمَا قَالَ " .
also referenced under: Hadith 2098 (Reference) & Volume 3, Book 11, Hadith 2098 (DarusSalam)