Undesirable vow

Q: I married a girl and after one year and eight (Part No. 23; Page No. 218) months of marriage she told me that she vowed at the age of thirteen that she would never marry a man who had another wife and if she did, she would observe Sawm (Fast) for a year. She did not tell her father before marriage about that vow. Now, she is asking if she is obliged to observe Sawm for a year or not as she was young when she made the vow. Now she is eighteen years old and is a married woman. As-salamu `alaykum warahmatullah wabarakatuh (May Allah's Peace, Mercy, and Blessings be upon you).

A: The vow made by this woman is undesirable. Thus, she has to offer Kaffarah (expiation) for not fulfilling it, which involves feeding ten Miskins (needy persons), or providing them with clothing, or emancipating a believing slave. If she is unable to afford any of these, she must observe Sawm for three days.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.