It may be interesting to hear Madame Guyon state the effect of this conversation in her own words.
Having said these words, the Franciscan left me. They were to me like the stroke of a dart, which pierced my heart asunder. I felt at this instant deeply wounded with the love of God; — a wound so delightful, that I desired it never might be healed. These words brought into my heart what I had been seeking so many years; or rather they made me discover what was there, and which I did not enjoy for want of knowing it. Oh my Lord! thou wast in my heart, and demanded only the turning of my mind inward, to make me feel thy presence. Oh, infinite Goodness! Thou wast so near, and I ran hither and thither seeking thee, and yet found thee not. My life was a burden to me, and my happiness was within myself. I was poor in the midst of riches, and ready to perish with hunger near a table plentifully spread and a continual feast. Oh Beauty; ancient and new! Why have I known thee so late? Alas, I sought thee where thou wast not, and did not seek thee where thou wast! It was for want of understanding these words of thy Gospel: 'The kingdom of God cometh not with observation, neither shall they say, Lo! here, or lo! there; for, behold, the kingdom of God is within you.' This I now experienced, since thou didst become my King, and my heart thy kingdom, where thou dost reign a Sovereign, and dost all thy will.
I told this good man, that I did not know what he had done to me; that my heart was quite changed; that God was there; for from that moment he had given me an experience of his presence in my soul, — not merely as an object intellectually perceived by any application of mind, but as a thing really possessed after the sweetest manner. I experienced those words in the Canticles: 'Thy name is as precious ointment poured forth; therefore do the virgins love thee.' For I felt in my soul an unction, which, as a salutary perfume, healed in a moment all my wounds. I slept not all that night, because thy love, oh my God! flowed in me like delicious oil, and burned as a fire which was going to destroy all that was left of self in an instant. I was all on a sudden so altered, that I was hardly to be known either by myself or others. I found no more those troublesome faults, or that reluctance to duty, which formerly characterized me. They all disappeared, as being consumed like chaff in a great fire.
I now became desirous that the instrument hereof might become my Director, in preference to any other. This good father, however, could not readily resolve to charge himself with my conduct, though he saw so surprising a change effected by the hand of God. Several reasons induced him to excuse himself: first, my person, then my youth, for I was only twenty years of age; and lastly, a promise he had made to God, from a distrust of himself, never to take upon himself the direction of any of our sex, unless God, by some particular providence, should charge him therewith. Upon my earnest and repeated request to him to become my Director, he said he would pray to God thereupon, and bade me do so too. As he was at prayer, it was said to him, 'Fear not that charge; she is my spouse.' This, when I heard it, affected me greatly. 'What! (said I to myself,) a frightful monster of iniquity, who have done so much to offend my God, in abusing his favors, and requiting them with ingratitude, — and now, thus to be declared his spouse!’ After this he consented to my request.
Nothing was more easy to me now than to practice prayer. Hours passed away like moments, while I could hardly do anything else but pray. The fervency of my love allowed me no intermission. It was a prayer of rejoicing and of possession, wherein the taste of God was so great, so pure, unblended and uninterrupted, that it drew and absorbed the powers of the soul into a profound recollection, a state of confiding and affectionate rest in God, existing without intellectual effort. For I had now no sight but of Jesus Christ alone. All else was excluded, in order to love with greater purity and energy, without any motives or reasons for loving which were of a selfish nature.
— edited from The Life of Madam Guyon Volume 1, Chapter 6.