12 So much must suffice for the present on the subject of the adorable and holy Trinity. It is not now possible to extend the enquiry about it further. Do ye take seeds from a humble person like me, and cultivate the ripe ear for yourselves, for, as you know, in such cases we look for interest. But I trust in God that you, because of your pure lives, will bring forth fruit thirty, sixty, and a hundred fold. For, it is said, Blessed are the pure in heart, for they shall see God. And, my brethren, entertain no other conception of the kingdom of the heavens than that it is the very contemplation of realities. This the divine Scriptures call blessedness. For “the kingdom of heaven is within you.”
The inner man consists of nothing but contemplation. The kingdom of the heavens, then, must be contemplation. Now we behold their shadows as in a glass; hereafter, set free from this earthly body, clad in the incorruptible and the immortal, we shall behold their archetypes, we shall see them, that is, if we have steered our own life's course aright, and if we have heeded the right faith, for otherwise none shall see the Lord. For, it is said, into a malicious soul Wisdom shall not enter, nor dwell in the body that is subject unto sin. And let no one urge in objection that, while I am ignoring what is before our eyes, I am philosophizing to them about bodiless and immaterial being. It seems to me perfectly absurd, while the senses are allowed free action in relation to their proper matter, to exclude mind alone from its peculiar operation. Precisely in the same manner in which sense touches sensible objects, so mind apprehends the objects of mental perception. This too must be said that God our Creator has not included natural faculties among things which can be taught. No one teaches sight to apprehend colour or form, nor hearing to apprehend sound and speech, nor smell, pleasant and unpleasant scents, nor taste, flavours and savours, nor touch, soft and hard, hot and cold. Nor would any one teach the mind to reach objects of mental perception; and just as the senses in the case of their being in any way diseased, or injured, require only proper treatment and then readily fulfil their own functions; just so the mind, imprisoned in flesh, and full of the thoughts that arise thence, requires faith and right conversation which make “its feet like hinds' feet, and set it on its high places.” The same advice is given us by Solomon the wise, who in one passage offers us the example of the diligent worker the ant, and recommends her active life; and in another the work of the wise bee in forming its cells, and thereby suggests a natural contemplation wherein also the doctrine of the Holy Trinity is contained, if at least the Creator is considered in proportion to the beauty of the things created.
But with thanks to the Father, the Son and the Holy Ghost let me make an end to my letter, for, as the proverb has it, πᾶν μέτρον ἄριστον.
Source: Letters (New Advent)