What is the ruling on building mosques with forbidden earnings?

Question:
Lately, there has been talk of singers building mosques. What is the ruling on that? And if it is forbidden, why is it not prevented?

Answer:
Building the mosque is valid even with that, but it should be spent from good wealth. If the construction is completed with forbidden money: from singing, or from a bank, or the like; it is valid and prayer is performed in it, and it does no harm. The sin is on the one who earned the forbidden money.
As for the mosque, it is a charitable cause, and so are charitable organizations. Lost money and money earned through improper means are spent in them; because they are lost money, money that has no owner in reality. So it is spent on repairing roads, on repairing restrooms, on charity for the poor, on paying off the debts of debtors, and on marrying off those in need; because it is nearly lost money, money that has no owner in reality.
And so is the dowry of a prostitute, and the fee of a fortune-teller, and so is what was taken from usury (riba) and Allah guided its owner; it is spent in the causes of righteousness. But it is recommended that mosques be kept pure from this, and that nothing be spent in them except good wealth. But when it is built from earnings that are not good; the prayer in it is valid and it is not demolished.