Is the sister entitled to claim a debt from her father, who passed away thirty years ago, knowing that she had previously stated that she forgave him, and she swore that she lent him money and that she did not forgive him, with her intention to expiate her oath? And is this money lawful for her?

Disputes are settled in Sharia courts, as a Mufti hears from only one party. Anyone who has a proven right against the deceased, and has not waived it, has the right to claim it before the judiciary.

If a debt is waived, it cannot be reclaimed, because what is waived does not return. A person's statement: "I forgive him" is not explicit in waiving the debt.

The rightful claimant may swear an oath to his right as long as he is truthful. However, swearing falsely is the "Al-Yamin al-Ghamus" (a perjurious oath), which is one of the gravest sins. What the swearer takes by it is not permissible for him, and expiation does not benefit him. Rather, repentance and returning the rights are obligatory, because a judge's ruling does not make unlawful things lawful. The Messenger of Allah, peace and blessings be upon him, said: "You come to me with your disputes, and perhaps some of you are more eloquent in presenting their arguments than others. So, if I rule in favor of someone a thing that rightfully belongs to his brother, based on his statement, then I am only cutting off a piece of hellfire for him, so let him not take it."