10 I had desired to enter the lists yet on other difficulties, but perhaps our minds are wearied out; when therefore I have advised you on those points which are useful to us for the hearing, both of what has been said, and of what is yet to be said, I again will hold my peace. What then are these points? I know that many have become confused by reason of the length of what has been spoken. Now this takes place when the soul is heavy laden with many burdens of this life. For as the eye when it is clear and transparent is keen-sighted also, and will not easily be tired in making out even the minutest bodies; but when from some bad humor from the head having poured into it, or some smoke-like fumes having ascended to it from beneath, a kind of thick cloud is formed before the ball, this does not allow it clearly to perceive even any larger object; so is naturally the case with the soul. For when it is purified, and has no passion to disturb it, it looks steadfastly to the fit objects of its regard; but when, darkened by many passions, it loses its proper excellence, then it is not easily able to be sufficient for any high thing, but soon is wearied, and falls back; and turning aside to sleep and sloth, lets pass things that concern it with a view to excellence and the life thence arising, instead of receiving them with much readiness.
And that you may not suffer this, (I shall not cease continually thus to warn you,) strengthen your minds, that you may not hear what the faithful among the Hebrews heard from Paul. For to them he said that he had “many things to say, and hard to be uttered”; not as though they were by nature such, but because, says he, “you are dull of hearing.” For it is the nature of the weak and infirm man to be confused even by few words as by many, and what is clear and easy he thinks hard to be comprehended. Let not any here be such an one, but having chased from him all worldly care, so let him hear these doctrines.
For when the desire of money possesses the hearer, the desire of hearing cannot possess him as well; since the soul, being one, cannot suffice for many desires; but one of the two is injured by the other, and, from division, becomes weaker as its rival prevails, and expends all upon itself.
And this is wont to happen in the case of children. When a man has only one, he loves that one exceedingly. But when he has become father of many, then also his dispositions of affection being divided become weaker.
If this happens where there is the absolute rule and power of nature, and the objects beloved are akin one with another, what can we say as to that desire and disposition which is according to deliberate choice; especially where these desires lie directly opposed to each other; for the love of wealth is a thing opposed to the love of this kind of hearing. We enter heaven when we enter here; not in place, I mean, but in disposition; for it is possible for one who is on earth to stand in heaven, and to have vision of the things that are there, and to hear the words from thence.
Source: Homilies on the Gospel of John (New Advent)