Sayyidah Aishah (may Allah be pleased with her) narrates from the Messenger of Allah (peace and blessings be upon him): "Whoever vows to obey Allah, let him obey Him, and whoever vows to disobey Him, let him not do so."
Imam al-Shafi'i (may Allah have mercy on him) says: The polytheists captured a woman of the Ansar and seized a she-camel of the Prophet (peace and blessings be upon him). The Ansari woman escaped on the she-camel of the Prophet (peace and blessings be upon him), and that woman had vowed to slaughter that she-camel of the Prophet (peace and blessings be upon him). When the Prophet (peace and blessings be upon him) came to know of it, he said: "There is no vow in disobedience, nor in what the son of Adam does not own."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجزية / 18852