What is the ruling on a husband monitoring his wife's and daughters' phones and their online pages, with their knowledge, in order to prevent corruption and activate his supervisory role and responsibility, and in accordance with the حديث (Hadith): "All of you are guardians, and all of you are responsible for your subjects"?

A husband is permitted to monitor his wife's and daughters' phones and their online pages with their knowledge, if the intention is to protect them and close the door to corruption. However, the basic principle is to have a good opinion of others, based on the Almighty's saying: "O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy."