7 Our Saviour's holy disciples, after getting beyond the limits of human thought, and then being purified by the word, are enquiring about the end, and longing to know the ultimate blessedness which our Lord declared to be unknown to His angels and to Himself. He calls all the exact comprehension of the purposes of God, a day; and the contemplation of the One-ness and Unity, knowledge of which He attributes to the Father alone, an hour. I apprehend, therefore, that God is said to know of Himself what is; and not to know what is not; God, Who is, of His own nature, very righteousness and wisdom, is said to know righteousness and wisdom; but to be ignorant of unrighteousness and wickedness; for God who created us is not unrighteousness and wickedness. If, then, God is said to know about Himself that which is, and not to know that which is not; and if our Lord, according to the purpose of the Incarnation and the denser doctrine, is not the ultimate object of desire; then our Saviour does not know the end and the ultimate blessedness. But He says the angels do not know; that is to say, not even the contemplation which is in them, nor the methods of their ministries are the ultimate object of desire. For even their knowledge, when compared with the knowledge which is face to face, is dense. Only the Father, He says, knows, since He is Himself the end and the ultimate blessedness, for when we no longer know God in mirrors and not immediately, but approach Him as one and alone, then we shall know even the ultimate end. For all material knowledge is said to be the kingdom of Christ; while immaterial knowledge, and so to say the knowledge of actual Godhead, is that of God the Father. But our Lord is also Himself the end and the ultimate blessedness according to the purpose of the Word; for what does He say in the Gospel? “I will raise him up at the last day.” He calls the transition from material knowledge to immaterial contemplation a resurrection, speaking of that knowledge after which there is no other, as the last day: for our intelligence is raised up and roused to a height of blessedness at the time when it contemplates the One-ness and Unity of the Word. But since our intelligence is made dense and bound to earth, it is both commingled with clay and incapable of gazing intently in pure contemplation, being led through adornments cognate to its own body. It considers the operations of the Creator, and judges of them meanwhile by their effects, to the end that growing little by little it may one day wax strong enough to approach even the actual unveiled Godhead. This is the meaning, I think, of the words “my Father is greater than I,” and also of the statement, “It is not mine to give save to those for whom it is prepared by my Father.” This too is what is meant by Christ's “delivering up the kingdom to God even the Father;” inasmuch as according to the denser doctrine which, as I said, is regarded relatively to us and not to the Son Himself, He is not the end but the first fruits. It is in accordance with this view that when His disciples asked Him again in the Acts of the Apostles, “When will you restore the kingdom of Israel?” He replied, “It is not for you to know the times or the seasons which the Father has put in His own power.” That is to say, the knowledge of such a kingdom is not for them that are bound in flesh and blood. This contemplation the Father has put away in His own power, meaning by “power” those that are empowered, and by “His own” those who are not held down by the ignorance of things below. Do not, I beg you, have in mind times and seasons of sense but certain distinctions of knowledge made by the sun apprehended by mental perception. For our Lord's prayer must be carried out. It is Jesus Who prayed “Grant that they may be one in us as I and Thou are one, Father.” For when God, Who is one, is in each, He makes all out; and number is lost in the in-dwelling of Unity.
This is my second attempt to attack the text. If any one has a better interpretation to give, and can consistently with true religion amend what I say, let him speak and let him amend, and the Lord will reward him for me. There is no jealousy in my heart. I have not approached this investigation of these passages for strife and vain glory. I have done so to help my brothers, lest the earthen vessels which hold the treasure of God should seem to be deceived by stony-hearted and uncircumcised men, whose weapons are the wisdom of folly.
Source: Letters (New Advent)