What is the ruling on a wife, for whom a marriage contract has been concluded, leaving without her husband’s knowledge, and to what extent is it permissible for her to go out in a car with her sister and her sister’s husband before the wedding, and what are her rights and duties towards him?

As long as the woman is in her father's house and her husband has not consummated the marriage with her, her obedience is to her family and not to her husband. Therefore, there is no blame upon her if she goes out without his knowledge. It is permissible for her to go out with her sister and her husband if there is no fear of temptation and the Sharia (definition) guidelines are observed, such as avoiding private seclusion (khalwa (definition)) and wearing the legal hijab (definition), because the sister's husband is a non-mahram (definition). However, it is not advisable to go against the husband's wishes if her going out in such a situation would displease him.