What is the religious ruling on the claim of a postpartum woman's impurity before 40 days have passed, and the impermissibility of her cooking for her household?

The statement that a woman in postpartum bleeding (nifas (definition)) or menstruation (hayd) is impure before purification is false and not part of the Muslim creed; rather, it is part of the Jewish creed. In the noble prophetic hadith (definition), it is mentioned that the Jews used to isolate themselves from menstruating women in food and dwelling. Then the verse was revealed: (And they ask you about menstruation. Say, "It is a discomfort, so keep away from women during menstruation. And do not approach them until they are pure.") The Prophet, peace and blessings be upon him, interpreted the verse by saying: "Do everything except intercourse," which indicates that the intended isolation is only from sexual intercourse, and everything else, such as eating together, sitting together, and dwelling together, is permissible.