Sayyidah Aishah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever vows an act of obedience, let him fulfil it; and whoever vows an act of disobedience, let him not fulfil it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النذور / 20089