Is it permissible to take the increase in the price of land sold by preemption, knowing that its original price was five thousand Riyals, and it was registered and paid for at eight thousand Riyals?

It is not permissible to deceive the pre-emptor (al-shafī‘) whether in writing or otherwise. He must be informed of the truth because Allah has obligated believers to advise one another and fulfill trusts. The Prophet, peace and blessings be upon him, said: "If they are truthful and clarify, they will be blessed in their transaction; but if they conceal and lie, the blessing of their transaction will be effaced." He also said: "A believer is a brother to a believer; he does not lie to him nor abandon him." And he said: "None of you truly believes until he loves for his brother what he loves for himself." Allah Almighty said: "Indeed, Allah commands you to render trusts to whom they are due." (Quran 4:58). Therefore, if a person buys something for a certain amount and then writes a higher amount when registering with the ruler to take more from the pre-emptor, this is not permissible.