4 As then we should all run together if we saw one from above bend down “on a sudden” from the height of heaven, promising to describe exactly all things there, even so let us be disposed now. It is from thence that this Man speaks to us; He is not of this world, as Christ Himself declares, “You are not of the world”, and He has speaking within him the Comforter, the Omnipresent, who knows the things of God as exactly as the soul of man knows what belongs to herself, the Spirit of holiness, the righteous Spirit, the guiding Spirit, which leads men by the hand to heaven, which gives them other eyes, fitting them to see things to come as though present, and giving them even in the flesh to look into things heavenly.
To Him then let us yield ourselves during all our life in much tranquillity. Let none dull, none sleepy, none sordid, enter here and tarry; but let us remove ourselves to heaven, for there He speaks these things to those who are citizens there. And if we tarry on earth, we shall gain nothing great from thence. For the words of John are nothing to those who do not desire to be freed from this swinish life, just as the things of this world to him are nothing. The thunder amazes our souls, having sound without significance; but this man's voice troubles none of the faithful, yea, rather releases them from trouble and confusion; it amazes the devils only, and those who are their slaves.
Therefore that we may know how it amazes them, let us preserve deep silence, both external and mental, but especially the latter; for what advantage is it that the mouth be hushed, if the soul is disturbed and full of tossing? I look for that calm which is of the mind, of the soul, since it is the hearing of the soul which I require. Let then no desire of riches trouble us, no lust of glory, no tyranny of anger, nor the crowd of other passions besides these; for it is not possible for the ear, except it be cleansed, to perceive as it ought the sublimity of the things spoken; nor rightly to understand the awful and unutterable nature of these mysteries, and all other virtue which is in these divine oracles.
If a man cannot learn well a melody on pipe or harp, unless he in every way strain his attention; how shall one, who sits as a listener to sounds mystical, be able to hear with a careless soul?
Source: Homilies on the Gospel of John (New Advent)