What is the ruling on a wife saving money from her husband without his knowledge, buying her necessities with it, and informing him that her father gifted it to her?

It is not permissible for a wife to take from her husband's money without his permission, unless he withholds her rightful due according to Islamic law, such as maintenance or clothing, or if he does not provide her with what is sufficient for her. In such cases, she may take what is customary and reasonable, based on the Prophet's (peace be upon him) saying to Hind: "Take what is sufficient for you and your child in a customary manner." If her husband asks her, she should speak indirectly and use allusions without resorting to outright lies.