A man asked Sayyiduna Imran bin Husayn (may Allah be pleased with him) about a man who had vowed that he would not attend the prayer in the mosque of his people. Sayyiduna Imran (may Allah be pleased with him) said to him: I heard the Messenger of Allah (peace and blessings be upon him) say: "There is no vow in a matter of sin, and its expiation is like the expiation for an oath."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15580