This isn't really a relic, per se: it's just an ordinary book written by Saint John Climacus.

Well, this version was written and published in Heaven, incorporated into its pages everything that the blessed soul could discover about the nature of angels and Heaven in three hundred years of patient questioning, and makes demons queasy just to look at it, but other than that, it's just an ordinary book.

The Ladder of Perfection is most often found in angelic Tethers, where it's assigned as a study aid to those attempting to shed dissonance. There's no real game benefit (although particularly benevolent GMs might allow someone who's constantly and exclusively studying the book to slightly increase the rate that they shed dissonance): it's mentioned for local color. However, as it is a level/0 relic, it can be used as the basis for unique artifacts. Many copies are minor reliquaries or talismans, for those angels with a scholarly bent.