11 Seek in the Father and Son a separation, you find none; no, not if you have mounted high; no, not even if you have reached something above your mind. For if you turn about among the things which your wandering mind makes for itself, you talk with your own imaginations, not with the Word of God; your own imaginations deceive you. Mount also beyond the body, and understand the mind; mount also beyond the mind, and understand God. Thou reachest not unto God, unless you have passed beyond the mind; how much less you reach unto God, if you have tarried in the flesh!
They who think of the flesh, how far are they from understanding what God is!— since they would not be there even if they knew the mind. Man recedes far from God when his thoughts are of the flesh; and there is a great difference between flesh and mind, yet a greater between mind and God. If you are occupied with the mind, you are in the midway: if you direct your attention beneath, there is the body; if above, there is God. Lift yourself up from the body, pass beyond even yourself.
For observe what said the psalm, and you are admonished how God must be thought of: “My tears,” it says, “were made to me my bread day and night, when it was said to me daily, Where is your God?” As the pagans may say, “Behold our gods, where is your God?” They indeed show us what is seen; we worship what is not seen. And to whom can we show? To a man who has not sight with which to see? For anyhow, if they see their gods with their eyes, we too have other eyes with which to see our God: for “blessed are the pure in heart, for they shall see God.” Therefore, when he had said that he was troubled, when it was daily said to him, “Where is your God?”
“these things I remembered,” says he, “because it is daily said to me, Where is your God?” And as if wishing to lay hold of his God, “These things,” says he, “I remembered, and poured out my soul above me.” Therefore, that I might reach unto my God, of whom it was said to me, “Where is your God? I poured out my soul,” not over my flesh, but “above me;” I transcended myself, that I might reach unto Him: for He is above me who made me; none reaches to Him but he that passes beyond himself.
Source: Tractates on the Gospel of John (New Advent)