The Ruling on Someone Who, from Ignorance, Changes His Father's Name for Some Worldly Benefit

Question :

What is the ruling concerning someone who, from ignorance, changes his father's name for some worldly benefit?

Answer:

If he changes his father's name to attribute himself to another father for prestige or just because he is ashamed to be associated with his father, he is committing a great sin - he is lying, distorting the facts, and disparaging his father. If he is trying to gain wealth by inheriting from somebody other than his father, then in this case as well, he is committing a great sin - he is lying, deceiving, and taking other people's wealth wrongly. Moreover, this can lead to great confusion over who is related to whom, creating the possibility of a wrongful marriage or wrongful acquisition of wealth. It is confirmed from Abu Dharr, may Allah be pleased with him, that the Prophet ﷺ said:
"There is nothing but Kufr (disbelief) for a man who claims fatherhood for other than his true father."

It is also confirmed from Sa'ad bin Abi Waqqas, may Allah be pleased with him, that the Prophet ﷺ said:
"Whosoever claims a man to be his father who is not truly his father, and knows that he is not his true father, Paradise will be forbidden for him."

It is also confirmed from Abu Hurairah, may Allah be pleased with him, that the Prophet ﷺ said:
"Don't be unwilling to accept your fathers, for whoever is unwilling to accept his father, is a disbeliever."

The Messenger of Allah ﷺ gave such a stern warning against this practice, that he called it disbelief and said that Paradise would be unlawful for him.

So whoever has done this should give it up and repent to Allah Almighty and seek His forgiveness.

Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 7 Pages 335-336