Is it permissible for a husband who is traveling to install surveillance cameras to monitor his wife and children in order to keep abreast of matters in his home?

A husband installing cameras in the home without the knowledge of his wife and adult children to monitor them and track their activities is impermissible. This is because it constitutes forbidden espionage, which is prohibited by Islamic law, as Allah Almighty says: "O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy," and as the Prophet (peace be upon him) said: "Do not envy one another, do not hate one another, and do not spy on one another." The Prophet (peace be upon him) also forbade a man from returning to his family at night to suspect them or seek out their faults.

The legitimate way to protect one's wife and children is to raise them with faith in Allah and His constant watchfulness, to accustom them to noble morals, and for the head of the household to be a good role model for them, so that Allah may protect him through them, as the Prophet (peace be upon him) said to Ibn Abbas: "Be mindful of Allah, and He will protect you."