The doctrine of the one person and two natures of Christ Our Lord, the answer to the questions, who and what He is, is vital to the understanding of what He did, and to the understanding of all that we ourselves are and do. So vital that we must examine it in more detail.
It was the Second Person of the Blessed Trinity who became man. Why was the Second Person chosen for the redemption of the world? There is a hint in the special relation of the Second Person to God's original plan of creation. God designed this creation according to the design of His intellect: from His intellect the Son of God proceeds within the Blessed Trinity. God made this universe as a finite mirroring of His own perfection: the Second Person of the Blessed Trinity is that same mirroring in the infinite. As St. John tells us in the prologue to his Gospel, “all things were made by the Word of God Who was with God and Who was God”. Given this special linking of one Person within the Blessed Trinity to God's original plan for this universe, it’s fitting that, the repairing of the damage from the sin of man, should fall to the same Person, and He who established all things should, in St. Paul's phrase, re-establish them. “Thus, it was the Word who became Flesh and dwelt among us that we, believing in His name, might be made the sons of God: as He was.”
God, the Son, took to Himself a human nature, making it His own as my nature is my own. We can express the new relation by saying that He, God the Son, became man. To the question what are you? He could answer "I am man". While not being the whole answer, not having reached His Divine Nature, it would have been wholly true. The relation, between His nature as man and His person, was as direct and intimate, as the relation between my nature and my person. He could say "I am man" as completely as I can say it, though He was more of a man than I: His human nature was not diminished by sin as mine is. This nature He took was a real human nature and a complete human nature. In reality the human nature of Christ actually belongs to us. His soul was a direct and individual creation of the Blessed Trinity, just like your soul and my soul; but by His body He was conceived of a human mother, just as you and I.
In the sense other human beings have a mother and father, He had a mother, Mary only. The effect upon the female element, normally produced by the male element, was produced simply by a creative act of the will of God. He is a member of Adam's race on His mother's side; He is a Jew on His mother's side; but not on His father's side. He was descended from Adam as we are, but not as much as we are. None of us derived our souls from Adam, but we all derived our bodies from Adam. He derived only His body from Adam. We are all related to Him through Mary, and only through her.
His was a real human nature and a complete human nature, lacking nothing. We read in Hebrews (4:15): “He has been through every trial, fashioned as we are, only sinless - sin not being required to complete human nature, but always operating to diminish it.” His body was a real body, though conceived by miracle. He was born an infant and grew through boyhood to manhood. His body He knew hunger and thirst; when His body was scourged, it bled; when it had a weight to bear too heavy for it, it fell. When His body was damaged beyond a certain point, it underwent the separation from the soul, which is death.
Just as He had a human body, He had a human soul to animate it, a soul which like other human souls was a created spirit. He could cry in the Garden of Gethsemane: "My soul is sorrowful even unto death". His soul had the faculties of intellect and will, a human intellect and a human will. He, who by His divine intellect had all wisdom, could in His human intellect, grow in wisdom. (Lk. 2:52) In the Garden He could say to God: "Not My will but Thine be done." Though His human will was totally united to the divine will, there was question of two wills and not one.
The co-existence of a human intellect with the divine intellect in Christ, at first, may seem more difficult to conceive than the co-existence of the two wills. A human intellect proceeds toward knowledge discursively, step by step. The external world makes its impact upon the bodily senses. From these senses the soul forms its concepts, and compares its concepts to form judgments. As its experience increases, its knowledge grows. It seems difficult to conceive that the one identical person, who by His divine nature knew all things, could also acquire by the operation of His human intellect, sparkles of the infinite light of knowledge in which He already lived. Hard to conceive, yet not inconceivable. The human nature and the divine nature belong to one person, but they are not one nature, as the one person could operate in both natures. If Our Lord wanted to lift a “load”, He could, either by His divine will or by the hard effort of the human muscles. Our Lord's human nature was a reality. His human senses and His human intellect were reality. His human senses could only receive the impact of the external world. His human intellect could only act on their evidence to form concepts and judgments. The Godhead did not swallow up the manhood.
The steady teaching of theologians has been that Our Lord's human intellect had both infused knowledge and the Beatific Vision. What it must have been like for the one human mind to move along so many roads at once. The point that neither infused knowledge nor beatific knowledge, are beyond the power of human nature to receive from God. Many men have had infused knowledge, though not continuously, and all saved will have beatific knowledge.
Our Lord, as man, had a real body with a real soul, real intellect and a real will. His emotions were also real. He loved St. John; wept over Jerusalem and over dead Lazarus, and He stormed at the Pharisees. Our Lord needed the supernatural life, too, to accomplish those things which are beyond the power of nature. Just as us, with His human natural power, He could not see God direct, but was capable of receiving sanctifying grace. The work of grace in the soul is, appropriated to the Third Person of the Blessed Trinity. The Second Person, as God, possessed all things; but as man He needed the indwelling of the Holy Spirit, both for that elevation and sanctification needed by every human nature. It would also provide the special guidance and illumination; His human nature needed for the unique work of the Son of God was to do, in it and through it. Our Lord had sanctifying grace in His soul. He did not have faith or hope, because by possessing the Beatific Vision He did not need them. He had charity in the fullest measure possible to a creature.
His charity, like all charity, was love of God and love of neighbor. His first recorded words are that strange answer to His mother in the temple, after being lost for three days: "Could you not tell that I must needs be in the place which belongs to my Father?" (Lk. 2:49) His last words as he was dying on the Cross were: "Father, into Thy hands I commend My spirit" (Lk. 11:46)
If Christ was God, in what sense was He praying to God? The Second Person of the Blessed Trinity was speaking to the other two Persons, but this converse within the Divine Nature is not the prayer we have in mind here, nor is it prayer at all. Christ also prayed as we pray, as the creature prays to the Creator. The difficulty here is that what is done in the nature is done by the Person. To say Christ prayed as the creature prayed to the Creator is to say that God the Son prayed the prayer of a creature. When God, the Son, took to Himself a human nature and was the Person in that nature, He took upon Himself all the obligations that a person has to his nature. One such obligation is to express its creatureliness to its Creator. His prayer was the expression of a human nature in all the relations that the human nature has to God; and because it was God Who uttered that human prayer, it was the perfect human prayer.
God and man, the Second Person of the Blessed Trinity is in our nature. Our Lord moves through the Gospels: thirty years of all but complete silence, and three years' healing, teaching, in crowds, with the Twelve or alone in the prayer of God, moving steadily towards the thing He had come to do. In Christ, God is showing Himself to us. Growth in the knowledge of Christ is growth in the knowledge of God, which He is; and of man, which He is. We cannot grow in the knowledge either of God or of man, if we do not grow in the knowledge of Christ. He is our best approach to the knowledge of God because, here God is to be studied not simply in His own nature, infinitely glorious but remote from our experience, but in our nature, finitely glorious and with experiences that we have shared. He is our best approach to the knowledge of man, because man, like everything else, is best studied in its most perfect specimen.
This growth in the knowledge of Our Lord requires that we get to know Him, as we know a person. This involves a knowledge that has to be personal. There is no such thing as an abstract knowledge of a person which all who know him possess. There is your and my knowledge of a person, and while we may both know him intimately, our knowledge will not be the same. Knowledge of a person is a relation between that person and us. Not only is it what is known about the person, but the reaction of our whole self, intellect, will and emotions to the person. Any number of men may know another man intimately, yet if they could compare their knowledge there would be vast surprises. As with any man: there are elements in him which one friend will respond to and another not, and those who do respond, will at different levels of intensity. This applies to Christ Our Lord because of the very perfection of His human nature, its depth and universality. No one of us can see and respond to all that is there, or see and respond to the same things in Him. What is vital for each one of us is that we develop our own closest possible personal knowledge of Him and personal relation with Him. I shall not attempt a description of the man Christ Jesus. It is for each one to develop His own personal intimacy by meeting Him. The first place to meet Him is in the Gospels.
In meeting Christ, we want to avoid the error of picturing Christ as all love – “love” in this context meaning a sentimental weakness about human beings. Meekness is a great and in-tensely dynamic virtue, so is mildness. In the English of today, “meek and mild" has frequently become a term of contempt for the type of character which, if not deserving contempt, at least merits no particular admiration. It implies a passivity, a willingness to be pushed about, an amiable desire for niceness all round. The twenty-third chapter of St. Matthew's Gospel, where you will find His terrifying attack upon the Scribes and Pharisees, could not more violently purge the mind of the picture of ineffective niceness. Love is a more complex thing, in itself and in Christ. In the Sermon on the Mount, (Mt. 5 to 7) everyone has heard of the eight opening phrases: Blessed are the poor in spirit, the patient, those who mourn, those who hunger and thirst for holiness, the merciful, the clean of heart, the peacemakers, those who suffer persecution in the cause of right. But practically nobody remembers that in the long sermon that follows these opening phrases, Our Lord threatens His hearers with hell no fewer than six times.
We must bring to our meeting with Christ no preconceived ideas of what He ought to be, but a determination to learn what He is. He is not to be measured by our standard, for He is the God Who made us. He is the standard.
Be careful of this phrase: Christ Our Lord was not a human person, though He had a human nature. The word personality, as used today, has gotten separated from the philosophical word person. It only means the general effect of a person's character and temperament. We must now consider a certain difficulty as we read the Gospels. The person rightly utters His nature, this one Person who had two natures, rightly utters each nature. The result is two quite different sets of utterances. He can say "I” and the Father are one", He can also say
"The Father is greater than “I". In the one case it is the "I" who totally owns the divine nature and expresses a fact about His divine nature. In the second case it is the same "I" who owns a human nature and expresses a fact about His human nature. We must habituate ourselves to this dual utterance, holding firmly in the mind that in either utterance the person speaking is God the Son, the Second Person of the Blessed Trinity. We must aim at a realization of the man who was God. We tend to concentrate on what it means that God took to Himself a human nature and became man. We must also consider what it must have meant to this man, really man as we are man, to know that He was God. We see what it meant to His apostles as they came gradually to be aware that the man was God, stunning their human minds, then revitalizing them with its glory. We must try to see also what it meant to Christ Himself to be aware that He was God, for it was with a human mind that He was aware of it, a mind as human as theirs.
What the blaze of the glory and the wonder of the knowledge must have been we can barely begin to conceive: but that bare beginning of conceiving we must attempt. Each must do it for himself. As the Apostles themselves grew to the knowledge of the fact, they could only be as utterly bewildered as we are. They saw him acting and speaking as man. They saw Him acting and speaking as man has no right to act and speak, as only God rightly could. They had no concept of one person with two natures, for there never had been such a person any more than there ever would be another.
Their bewilderment was not the difficulty of reconciling two sets of statements from the same person, one entirely true of Him as God, one entirely true of Him as man. Until they realized that He was God, they must have been uncertain even of His virtue as man. The phrase "Christ was not God but He was the perfect man", can surely only be the product of a long and heroic abstention from Gospel reading. If He was not God, He was not a perfect man.
Consider one phrase only: "He that loveth father and mother more than Me is not worthy of Me". If the speaker was not God then he was a man of an egoism, that no word short of insanity would fit it. If He was God, then He was perfect man; if He was not then He was a very arrogant man. We know what the Apostles came to know: He was God, and all falls in place.
He was man, but He was different. The difference was also that He had a divine nature in which also He acted and spoke. Though the divine nature and the human did not mingle, in the activity of the human nature, many things were different by necessity because the person whose nature it was God. He loved the companionship of the Apostles, and they loved His companionship. He knew the difference and they felt His difference. He never asked their advice; never argued with them or with anyone. He was the Master and He taught, and men must either accept His teaching or reject it: there was no place for argument about it. He never prayed with His Apostles. He taught them how to pray, but His own prayer was alone with the Father. They loved Him as no other man has ever been loved, though still not in the measure of His love for them. They were desolate without Him. And the one of them that He loved most summarized the doctrine of Christ's Godhead and his own experience of Christ in the key-phrase of all religion - God is Love.