What is the ruling regarding money acquired through illicit means, when its owner repents but is unable to return it for fear of ruin? Will Allah forgive him if he donates it as charity, and is the building constructed with it lawful, and is it permissible for him to spend the remainder of it on furniture that has been mixed with his lawful money?

The ruling on ill-gotten wealth is determined based on the method of its acquisition: 1. Acquired through usurpation or theft: It must be returned to its rightful owners. Giving it as charity is not sufficient as long as its return is possible. Deception can be used to return it without specific identification. 2. Acquired with the owner's consent (e.g., usury): If the recipient was unaware of its unlawfulness at the time of acquisition, they are not required to dispose of it upon repentance. If the recipient was aware of its unlawfulness, they must dispose of it by giving it as charity to the poor or spending it on general Muslim welfare.

In the latter case, the ill-gotten wealth must be quickly spent on charitable causes. Whoever delays keeping it commits a sin. A house and furniture purchased with ill-gotten wealth can be used, because the unlawfulness is attached to the person's responsibility, not to the item itself.