Shaykh Ibn Uthaymeen was asked:
What is the ruling on overtime at work and does it have legislated principles? Does writing that I performed overtime when I did not do so enter into the category of unlawful wealth?
“Overtime is in accordance to the system; however, if a person takes a compensation for it and he did not perform it, then this compensation is unlawful for him. It is consuming wealth in falsehood. Adding to that is lying in terms of affirming that he worked when he did not work. In addition to that is that perhaps he will become a bad example for others who are hesitatant about this impermissible action. If they see another person perform it, the affair will become easier because taking others as an example [in evil] leads to trivializing calamities and disobedience. Just like taking others as examples [in good] can also strengthen one upon obedience. So like this, the one who calls to good, has the reward similar to the one who does it”.
[‘Ilaam al-Musaafireen (pg.98-99)]
Faisal Ibn Abdul Qaadir Ibn Hassan