7 What then, beloved, are we going to explain that which we have asked, how the Word sees, how the Father is seen by the Word, what the seeing of the Word is? I am not so bold, so rash, as to promise to explain this, for myself or for you: however I estimate your measure, still I know my own. Therefore, if you please, not to delay it longer, let us run over the passage, and see how carnal hearts are troubled by the words of the Lord; to this end troubled, that they may not continue in that which they hold.
Let this be wrested from them, as some toy is wrested from children, with which they amuse themselves to their hurt, that, as persons of larger growth, they may have more profitable things planted in them, and may be able to make progress, instead of crawling on the earth. Arise, seek, sigh, pant with desire, and knock at what is shut. But if we do not yet desire, not yet earnestly seek, not yet sigh, we shall only be throwing pearls to all indiscriminately, or finding pearls ourselves, regardless of what kind.
Wherefore, beloved, I would move a longing desire in your heart. Good character leads to right understanding: the kind of life leads to another kind of life. One kind of life is earthly, another is heavenly: there is a life of beasts, another of men, and another of angels. The life of beasts is excited with earthly pleasures, seeks earthly pleasures alone, and grovels after them with immoderate desire: the life of angels is alone heavenly; the life of men is midway between that of angels and of beasts.
If man lives after the flesh, he is on a level with the beasts; if he lives after the Spirit, he joins in the fellowship of angels. When you live after the Spirit, examine even in the angelic life whether you be small or well-grown. For if you are still a little one, the angels say to you, “Grow: we feed on bread; you are nourished with milk, with the milk of faith that you may come to the meat of sight.” But if there be still a longing for filthy pleasures, if the thoughts be still of deceit, if lies are not avoided, if perjuries be heaped on lies, shall a heart so foul dare to say, “Explain to me how the Word sees;” even if I be able to do so, even if I myself now see?
And further, though not perhaps of this character myself, and I am nevertheless far from this vision, how must that man be weighed down with earthly desires, who is not yet rapt with this desire from above! There is a wide difference between loathing and desiring; and again, between desiring and enjoying. If you live as do the beasts, you loathe; the angels have full enjoyment. If, on the other hand, you live not as the beast, you have no longer loathing: something you desire, and dost not receive: you have, by the very desire, begun the life of the angels. May it grow in you, and be perfected in you; and may you receive this, not of me, but of Him who made both me and you!
Source: Tractates on the Gospel of John (New Advent)