Is it permissible to borrow from money that is suspected of being unlawful with the intention of paying it back later?

If the money your friend obtained is unlawful, such as usurious interest or the price of something forbidden, then it must be disposed of by spending it on the welfare of Muslims or giving it to the poor and needy, with the intention of disposal, not charity. If you are poor and in need, it is permissible for you to take from this money and own it without compensation, because it becomes lawful and pure for the poor. This money must not be destroyed; rather, it must be spent on the welfare of Muslims.