The account which she gives of her inward state at this time, is an exceedingly painful one.
I readily gave way, to sallies of passion. I failed in being strictly conscientious and careful in the utterance of the truth. I became not only vain, but corrupt in heart. Although I kept up some outward religious appearances, religion itself, as a matter of inward experience, had become to me a matter of indifference. I spent much time, both day and night, in reading romances, those strange inventions to destroy youth. I was proud of my personal appearance, so much so that, contrary to my former practices, I began to pass a good deal of my time before the mirror. I found so much pleasure in viewing myself in it, that I thought others were in the right, who practiced the same. Instead of making use of this exterior, which God gave me as a means of loving him more, it, became to me the unhappy source of a vain and sinful self-complacency. All seemed to me to look beautiful in my person; but in my declension and darkness I did not then perceive, that the outward beauty covered a sinful and fallen soul.But this was not the judgment which the world then passed upon her; the world so severe in the exaction of its own claims, but so indulgent in mitigating the claims of God. Under a form that was outwardly beautiful, and veiled by manners that had received the most correct and advantageous culture, it was not easy for man to perceive the elements and workings of a heart which harbored moral and religious rebellion. In the eye of the world, therefore, which is but imperfectly capable of penetrating beyond the exterior, and which delights in elegance of form and perfection of manners, there was but little to blame, and much to praise; but in the eye of God, which sees and estimates the inmost motive, it was not possible for outward beauty to furnish a compensation for inward deformity. And in using the phrase inward deformity, we do not necessarily mean, that she was worse than many others who have a reputation for good morals. Estimating her by the world's standard, she had her good qualities, as well as those of an opposite character, her excellences as well as her defects. Nevertheless, there was that wanting which constitutes the soul's true light, without which all other beauty fades, and all other excellence is but excellence in name, — the love of God in the heart.
— edited from The Life of Madam Guyon (1847) Volume 1, Chapter 3.