12 Consider the body: it is mortal, earthy, weak, corruptible; away with it. Yes, perhaps you say, but the body is temporal. Think then of other bodies, the heavenly; they are greater, better, more magnificent. Look at them, moreover, attentively. They roll from east to west, they stand not; they are seen with the eyes, not only by man, but even by the beast of the field. Pass beyond them too. And how, do you say, pass beyond the heavenly bodies, seeing that I walk on the earth?
Not in the flesh do you pass beyond them, but in the mind. Away with them too: though they shine ever so much, they are bodies; though they glitter from heaven, they are bodies. Come, now that perhaps you think you have not whither to go, after considering all these. And whither am I to go, do you say, beyond the heavenly bodies; and what am I to pass beyond with the mind? Have you considered all these? I have, do you say. By what means have you considered them? Let the being that considers appear in person.
The being that considers all these, that discriminates, distinguishes, and in a manner weighs them in the balance of wisdom, is really the mind. Doubtless, then, better is the mind with which you have contemplated all these things, than these things which you have contemplated. This mind, then, is a spirit, not a body. Pass beyond it too. And that you may see whither you are to pass beyond, compare that mind itself, in the first place, with the flesh. Heaven forbid that you should deign so to compare it!
Compare it with the brightness of the sun, of the moon, and of the stars; the brightness of the mind is greater. Observe, first, the swiftness of the mind; see whether the scintillation of the thinking mind be not more impetuous than the brilliance of the shining sun. With the mind you see the sun rising. How slow is its motion compared with your mind! What the sun is about to do, you can think in a trice. It is about to come from the east to the west; tomorrow rises from another quarter.
Where your thought has done this, the sun still lags behind, and you have traversed the whole journey. A great thing, therefore, is the mind. But how do I say is? Pass beyond it also. For the mind, notwithstanding it be better than every kind of body, is itself changeable. Now it knows, now knows not; now forgets, now remembers; now wills, now wills not; now errs, now is right. Pass therefore beyond all changeableness; not only beyond all that is seen, but also beyond all that changes.
For you have passed beyond the flesh which is seen; beyond heaven, the sun, moon, and stars, which are seen. Pass, too, beyond all that changes. For when you had done with those things that are seen, and had come to your mind, there you found the changeableness of your mind. Is God at all changeable? Pass then, beyond even your mind. Pour out your soul “above you,” that you may reach unto God, of whom it is said to you, “Where is your God?”
Source: Tractates on the Gospel of John (New Advent)