Does the earnings of a guard who disobeys his manager's instructions by entering the building instead of standing outside become affected, and does his money become unlawful, and how can he rectify that?

The presence of the guard outside the building has two scenarios:

1. If being outside the building is not a condition or a customary practice, then the guard’s disobedience of the manager’s order does not affect his salary as long as he has performed his duty. "The principle of contracts is that a servant is not obligated to anything unless he commits to it, or unless the Lawgiver obligates him." Nevertheless, it is better for the guard to adhere to the manager’s orders for the sake of order.

2. If being outside the building is a condition or a customary practice, then the guard’s entering the building is a dereliction of his duty. He must seek absolution for the times he was remiss, based on the Almighty’s saying: (Indeed, Allah commands you to render trusts to whom they are due) and His saying: (O you who have believed, fulfill [all] contracts), and the saying of the Messenger of Allah, peace and blessings be upon him: (Muslims are bound by their stipulations).