Is it permissible for a wife to demand the money she lent to her husband, knowing that he has sufficient funds?

There is no objection to the wife demanding her money from her husband, as it is her exclusive right.

However, the following should be observed:

1. The wife should not put pressure on her husband merely because he wishes to marry a second wife.

2. The financially distressed debtor should not be pressed for his debt, as Allah Almighty says: "And if there is one in [financial] hardship, then [let there be] postponement until [a time of] ease."

3. A wealthy debtor should not procrastinate in paying his debt, as the Prophet, peace and blessings be upon him, said: "The procrastination of the rich [in paying debt] is injustice."

4. The husband should not marry with his wife's money. He must first repay the debt, and then, if he has remaining money, he may marry.