The passage is translated in Marginal Modernity by Lisi, p.73-4 from Frank's Einführung in die frühromantische Ästhetik, p. 242-3. I do not have access to Frank's book to track the original citation.
Both Schelling and Hegel came to the idea by reflecting on Fichte's (supposedly) "bad infinity" of self's constant oscillation between the finite and the infinite, subjective and absolute, necessity and freedom, see Steinrueck, Fichte's "Bad Infinity". And they both offer unifications from an "absolute" perspective, that "overcomes" attempting to define the infinite against the finite.
Here is Schelling's passage:
"The single link in a chain has a value, but it has it through another, which again has it through another and so on to infinity; the value of each link is accordingly conditioned through an infinite sequence, which itself is preposterous and which will never be actualized, and each link therefore only means something because one is certain that it will never be necessary to realize the value of the whole, or be possible to reach the final link, at which point the entirety of the supposed science would dissolve itself into a complete nothing."
The debt illustration, which appears in a footnote to this passage, is by what came to be known as the pyramid scheme in modern business:
"Like the English state debt. Continual borrowing from a second, in order to pay the first, from a third, in order to pay the second".
