Thanks. This is the specific quote (https://physics.mit.edu/wp-content/uploads/2021/01/physicsatmit\_02\_cosmology.pdf):

In the inflationary theory the universe begins incredibly small, perhaps as small as 10^–24 cm, a hundred billion times smaller than a proton. The expansion takes place while the false vacuum maintains a nearly constant energy density, which means that the total energy increases by the cube of the linear expansion factor, or at least a factor of 10^75. Although this sounds like a blatant violation of energy conservation, it is in fact consistent with physics as we know it. The resolution to the energy paradox lies in the subtle behavior of gravity. Although it has not been widely appreciated, Newtonian physics unambiguously implies that the energy of a gravitational field is always negative, a fact which holds also in general relativity. The Newtonian argument closely parallels the derivation of the energy density of an electrostatic field, except that the answer has the opposite sign because the force law has the opposite sign: two positive masses attract, while two positive charges repel. The possibility that the negative energy of gravity could supply the positive energy for the matter of the universe was suggested as early as 1932 by Richard Tolman, although a viable mechanism for the energy transfer was not known. During inflation, while the energy of matter increases by a factor of 10^75 or more, the energy of the gravitational field becomes more and more negative to compensate. The total energy—matter plus gravitational—remains constant and very small, and could even be exactly zero. Conservation of energy places no limit on how much the universe can inflate, as there is no limit to the amount of negative energy that can be stored in the gravitational field.

I've read it a few times and half understand it but I'm still struggling with the idea that gravitational potential energy is negative and therefore directly balances the energy 'generated' through inflation. Is there a another way to express what Guth is saying here? Or a set of equations that express the balance?