Abu Hurayrah (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) said: "A vow does not bring the son of Adam closer to anything that Allah has not decreed for him; rather, the vow coincides with the decree, and by it wealth is extracted from the miser which the miser did not intend to give."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النذور / 20104