It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "There is no vow in a matter of sin nor in a state of anger, and its expiation is the expiation of an oath."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15454