Is it permissible to borrow from an Islamic bank for marriage, given the lack of funds for its expenses, and is dealing with Islamic banks considered usury?

It is permissible to borrow from an Islamic bank if it offers interest-free loans (qard hassan). There is also no objection to engaging with it in a Murabaha to the Purchase Orderer (Murabaha lil-amir bi al-shira') transaction to obtain cash (Tawarruq). The statement that Islamic and usurious banks are the same is incorrect. Islamic banks are a legitimate alternative, provided they adhere to the rulings of Islamic law and the directives of Shariah supervision.