What is the ruling on buying girls and holding them in pawn to work in dance clubs, and what is the ruling on money earned from that?

It is not permissible to buy a free woman; the contract of selling her is void by consensus, due to Allah's saying: "There are three whose adversary I am on the Day of Resurrection: a man who sells a free person and consumes their price." As for marrying her to prevent her from falling into sin, it is a great act of devotion, provided that she is chaste, and that her guardian (father, then relatives, then the ruler) approves the marriage. It is also not permissible to enter nightclubs where sacred limits are violated, except for the purpose of denouncing them, due to the wrath of Allah involved, as He says: "And He has already revealed to you in the Book that when you hear the verses of Allah being denied and ridiculed, then do not sit with them until they enter into another conversation. Indeed, in that case, you would be like them."