Is it permissible to obligate employees to cover for their absent colleagues without compensation, while deducting the absent employee's salary for the benefit of the institution? And what is the ruling on a manager who implements these instructions?

For a specific employee, such as a staff member, it is permissible to refuse tasks exceeding what was agreed upon, even if they are during official working hours, unless there is a condition or custom that necessitates them. This is similar to how a shepherd is not obligated to tend to newborn lambs unless there is a condition or custom. Therefore, an employee is not required to perform the duties of an absent colleague unless compensated or if there is a condition in the contract or a work custom. If there is injustice in assigning extra tasks without compensation, the sin falls upon the company owner, and the assistant manager is also sinful for aiding in what is forbidden.