… is from David Hume’s 1742 essay “Of Public Credit,” (here from page 350 of the 1985 Liberty Fund collection of Hume’s essays, edited by the late Eugene Miller, Essays: Moral, Political, and Literary) (original emphasis):
[O]ur modern expedient, which has become very general, is to mortgage the public revenues, and to trust that posterity will pay off the incumbrances contracted by their ancestors: And they, having before their eyes, so good an example of their wise fathers, have the same prudent reliance on their posterity; who, at last, from necessity more than choice, are obliged to place the same confidence in a new posterity.
