What is the ruling on a wife serving her husband's mother, and is the husband sinful if he leaves his wife to eat alone and, out of filial piety towards his parents, eats with them? Is the husband's mother entitled to question the wife about what she takes from the marital home in the husband's absence?

The wife is not obligated to serve her husband's mother; if she does so, it is an act of righteousness for which she will be rewarded. There is no harm for the husband in leaving his wife to eat with his parents, as an act of kindness towards them, and the rights of parents take precedence over the rights of the wife. Eating with the wife is recommended but not obligatory, and this recommended act is not given precedence when it conflicts with honoring one's parents. It is the wife's right to go to her apartment and reside there, even if her husband travels, and her husband's mother has no right to prevent her from doing so or to restrict her.