Concerning the Ten Commandments, which are the Heads of the Law (146-148)

And when any one, having conceived an idea of some good which is not present, hastens to lay hold of it, he then drives his soul forward to a great distance, and extending it in the greatest possible degree, from his anxiety to attain the object of his desires, he is stretched as it were upon the rack, being anxious to lay hold of the thing, but being unable to reach it, and being in the same condition with those who are pursuing people who are running away, following with an inferior speed, but with unrivalled eagerness.

And something of the same kind appears to happen, also, with respect to the external senses; for very frequently the eyes, hastening to come to the comprehension of something which is removed to a great distance, strain themselves, exerting themselves to the very fullest extent of and even beyond their power, are unsuccessful, and grow dim in the empty space between themselves and their object, wholly failing in attaining to an accurate knowledge of the subject before them, and moreover impairing and injuring their sight by the exceeding intensity of their efforts and steady gaze.

And, again, sometimes when an indistinct noise is borne