What is the ruling on a wife completing her mixed-gender education, which her family stipulated she complete before marriage? And is she obliged to obey her parents in completing her studies, or to obey her husband who rejects such mixing? And what is the ruling on the husband reneging on his condition after marriage?

The wife's condition that she completes her studies, stipulated to the husband, is a valid and binding condition. The wife has the right to annul the marriage if the husband violates it. Fulfilling the condition is considered commendable by the Hanbalis, while Ibn Taymiyyah views it as obligatory. However, if the studies involve impermissible (shar'i) acts, then fulfilling the condition is not permissible. In this case, there is no blame on the wife for disobeying her mother, as obedience to the husband takes precedence over obedience to parents when there is a conflict, and "there is no obedience to a creature in disobedience to the Creator." But if it is possible to complete the studies in a place where there is no mixing (of genders) or impermissible (shar'i) acts, then the husband should allow her to complete her studies, in fulfillment of the condition and to please her mother.