Q&A: Loan

Some trading and manufacturing companies get loans from private or state banks in Muslim countries and also from other [non-Muslim] institutions with the condition of interest; and they also earn interest on the deposits they leave in those banks. Are we allowed to buy shares from these companies or be partners in their ventures?

Banks in the West give loans —known as mortgage— to those who do not have enough money to buy houses; this is to be paid back in [weekly or monthly] instalments with a high rate of interest. Is a Muslim allowed to use this facility? If it is not permissible, is there a solution in your view for someone who claims that he needs the mortgage to buy his own residential house and does not possess enough money to pay for it?