Is it permissible for a father to compel his children to buy from him at a price higher than the market price, and to consider them disobedient should they refuse, claiming that the increase in price is an act of filial piety?

For a sale to be valid, mutual consent is a prerequisite, based on the Almighty's saying: ﴿إِلَّا أَن تَكُونَ تِجَارَةً عَن تَرَاضٍ مِّنكُمْ﴾ [“unless it be a trade by mutual consent among you”], and the Prophet's (PBUH) saying: "Indeed, a sale is only by mutual consent." Therefore, a father has no right to compel his son to buy from him, nor to accept a price he does not agree to, as this invalidates the sale. The son's refusal is not considered disobedience; rather, he has the right to refuse to buy or to give his father anything from his wealth.

However, a father may take from his son's wealth under specific conditions: 1. The father must be in need of the son's wealth. 2. It must not harm the son; thus, he should not take what the son needs. 3. He should not take from him to give to his brother.

This is supported by the hadith (definition): "You and your wealth belong to your father," and the Prophet's (PBUH) saying: "Indeed, your children are a gift from Allah to you... they and their wealth are yours if you are in need of them." The son must be gentle with his father and interact with kindness and leniency, without harshness or ill manners.