What is the ruling on leaving work before the official end of working hours—whether with genuine or fabricated assignments—and what is the ruling on the salary resulting from that?

Public sector employees must adhere to honesty and perform their work to the fullest extent according to the instructions of the authorities they report to, in fulfillment of contracts and conditions, for Allah Almighty says: "O you who have believed, fulfill [all] contracts," and based on the hadith: "Muslims are bound by their conditions." It is not permissible to obey an official if he abuses his position or oversteps his authority, for Allah Almighty says: "O you who have believed, upon you is [the responsibility for] yourselves. Those who have gone astray will not harm you when you have been guided." And part of guidance is enjoining what is right and forbidding what is wrong. If an employee leaves his work before the end of the term without permission, he is not entitled to any wages except for the amount of work he has performed.