Is a mother sinful if she takes money from her husband without his knowledge to provide for her children's needs, such as clothing and supplies, and what is the ruling on her action?

If a man does not provide the obligatory maintenance for his wife and children, it is permissible for her to take from his money what suffices her and her children, within reasonable bounds, based on the hadith of Hind bint Utbah. This includes clothing and essential living necessities such as sleeping mats, seating, a refrigerator, and gas, and so forth. If the husband does not provide these, it is permissible for her to take money without his knowledge to purchase what is necessary for her. The general rule is that it is not permissible to take a husband's money without his knowledge, except in the case of obligatory maintenance.