Today is the feast of St. Teresa of Avila, Doctor of the Church. From her Life, Chapter XL:
The Truth of which I am speaking, and which I was given to see, is Truth Itself, in Itself. It has neither beginning nor end. All other truths depend on this Truth, as all other loves depend on this love, and all other grandeurs on this grandeur. I understood it all, notwithstanding that my words are obscure in comparison with that distinctness with which it pleased our Lord to show it to me. What think you must be the power of His Majesty, seeing that in so short a time it leaves so great a blessing and such an impression on the soul? O Grandeur! Majesty of mine! what is it Thou art doing, O my Lord Almighty! Consider who it is to whom Thou givest blessings so great! Dost Thou not remember that this my soul has been an abyss of lies and a sea of vanities, and all my fault? Though Thou hadst given me a natural hatred of lying yet I did involve myself in many lying ways. How is this, O my God? how can it be that mercies and graces so great should fall to the lot of one who has so ill deserved them at Thy hands?
Once, when I was with the whole community reciting the Office, my soul became suddenly recollected, and seemed to me all bright as a mirror, clear behind, sideways, upwards, and downwards; and in the centre of it I saw Christ our Lord, as I usually see Him. It seemed to me that I saw Him distinctly in every part of my soul, as in a mirror, and at the same time the mirror was all sculptured—I cannot explain it—in our Lord Himself by a most loving communication which I can never describe. I know that this vision was a great blessing to me, and is still whenever I remember it, particularly after Communion.
I understood by it, that, when a soul is in mortal sin, this mirror becomes clouded with a thick vapour, and utterly obscured, so that our Lord is neither visible nor present, though He is always present in the conservation of its being. In heretics, the mirror is, as it were, broken in pieces, and that is worse than being dimmed. There is a very great difference between seeing this and describing it, for it can hardly be explained. But it has done me great good; it has also made me very sorry on account of those times when I dimmed the lustre of my soul by my sins, so that I could not see our Lord.