"There is no vow to commit an act of disobedience, and no vow concerning that which the son of Adam does not possess."  

أَنَّ النَّبِيَّ ﷺ قَالَ لاَ نَذْرَ فِي مَعْصِيَةِ اللَّهِ وَلاَ فِيمَا لاَ يَمْلِكُ ابْنُ آدَمَ  

"Whoever swears by a religion other than Islam, telling a lie, will be as he said, and whoever kills himself with something, he will be punished with it in the Hereafter, and there is no vow concerning that which a man does not possess."  

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ حَلَفَ بِمِلَّةٍ سِوَى مِلَّةِ الإِسْلاَمِ كَاذِبًا فَهُوَ كَمَا قَالَ وَمَنْ قَتَلَ نَفْسَهُ بِشَىْءٍ فِي الدُّنْيَا عُذِّبَ بِهِ يَوْمَ الْقِيَامَةِ وَلَيْسَ عَلَى رَجُلٍ نَذْرٌ فِيمَا لاَ يَمْلِكُ