What is the ruling of Islamic law regarding a person borrowing a sum of money from another person who has taken out an interest-based loan from a bank, on the condition that the same amount be repaid to him?

It is not permissible to borrow money from someone who obtained it through a usurious contract, because dealing with someone who possesses purely unlawful money in the very essence of that unlawful money is forbidden. One must avoid dealing with him regarding this money in any way (selling, buying, lending, gifting), because you would be taking money that was acquired without a legitimate cause. In doing so, there is an implicit approval and encouragement for the usurer to continue his action. He must be advised and warned against the sin of usury.