And among the followers of the Book there are some such that if you entrust one (of them) with a heap of wealth, he shall pay it back to you; and among them there are some such that if you entrust one (of them) with a dinar he shall not pay it back to you except so long as you remain firm in demanding it; this is because they say: There is not upon us in the matter of the unlearned people any way (to reproach); and they tell a lie against Allah while they know.