"They do not bring any good; they are just a means of taking wealth from the miserly."  

أَنَّ رَسُولَ اللَّهِ ﷺ نَهَى عَنِ النَّذْرِ وَقَالَ إِنَّهُ لاَ يَأْتِي بِخَيْرٍ إِنَّمَا يُسْتَخْرَجُ بِهِ مِنَ الْبَخِيلِ  

"The Messenger of Allah forbade vows and said: 'They do not change anything; they are just a means of taking wealth from the miserly.'"  

نَهَى رَسُولُ اللَّهِ ﷺ عَنِ النَّذْرِ وَقَالَ إِنَّهُ لاَ يَرُدُّ شَيْئًا إِنَّمَا يُسْتَخْرَجُ بِهِ مِنَ الشَّحِيحِ