Three hundred years after Jesus left Palestine, Christian leaders held heated debates about his nature, rejecting some ideas about Jesus and finally settling upon an official view.
Some early Christians claimed Jesus was only human. Some said he was only divine. Some said he was half human--the half that needed food and sleep and felt grief to the point of tears and experienced terror at the thought of his own death. Some said Jesus was half divine--the half that could stroll upon the top of a deep lake and feed ten thousand people with a pond perch and two pitas and appear in an otherworldly vision with Moses and mix vats of clear water into marvelous Bordeaux.
Still others said Jesus was 'fully' human and 'fully' divine, and though this position makes as much sense as a man saying he is fully male and fully female, this view won the day to became the official teaching of orthodox Christianity.
It was impossible to keep these two aspects of Jesus in a perfect balance because in the very affirmation of divinity his humanity is compromised, and in the affirmation of his humanity his divinity is compromised.
Look at it this way:
If the historical Jesus, the boy and man who walked the gritty pathways of first-century Palestine, was fully divine and was God, we must ask: Did Jesus know everything, like God in his omniscience knows everything? Did the historical Jesus of Palestine know the distance to the sun in summertime--in miles, in yards? Did he know calculus? Did he know the formula for penicillin? Did the historical Jesus of Palestine know all languages, past, present and future? Did he know that China, Australia, and the Americas existed? Did he know all the thoughts of every human who was alive while he was on earth? Did he know that a man called Kennedy would be assassinated in a year called 1963 in a city called Dallas? Even as an infant, Jesus was God. Did the infant Jesus, the one-minute-old Jesus, know all of the above?
If the historical Jesus, the boy and man who walked the gravelly pathways of first-century Palestine, was fully divine and was God, we must ask: Could Jesus do anything, as God in his omnipotence can do anything? Could Jesus throw a pebble to the moon? Could he level a mountain with a word? Could he raise the plains of western Nebraska to the height of Mount Annapurna or Everest? Could he eradicate all diseases? Could he make another universe out of nothing? Could he destroy the current universe? Could he create another God, if he had wanted to? Could the historical Jesus of Palestine construct a piano and play Rachmaninoff's 'Prelude in C-sharp minor' on it? Even as an infant, Jesus was God. Could the infant Jesus, the one-minute-old Jesus, do all of the above?
If you say YES to all of this and claim Jesus knew all of this and could do all of this, you invariably diminish the 'full' humanity of Jesus because no one who is 'fully' human and living in first-century Palestine could know and do any of these. If you say NO to all of this and claim Jesus knew none of this and could not do any of this, you necessarily diminish the 'full' divinity of Jesus because any God who is 'fully' God knows all and can do all.
Saying Jesus is fully divine and fully human is an illogicality that does not even rise to the level of a 'seeming' paradox and cannot be rectified--except (!) possibly by a mid-first-century notion offered by Paul in a Letter to the Philippians (collected with other letters of his in the Christian New Testament Bible). Paul says:
In your relationships with fellow Christians, have the same attitude as Jesus. In his very nature Jesus was God, but he did not consider equality with God something to be used for his own advantage. Instead, he emptied himself of his divine privileges. He took the humble position of a slave and was born as a human being. When he appeared in human form, he humbled himself in obedience to God and died a criminal's death on a cross. (2: 5-8)
Paul's idea is that God became a human and subjected himself to all the impairments and parameters of being human. And that MUST mean the man Jesus was ignorant and weak, like all the other bipedal humanoids who chewed with a tooth and peeped through eyes.
Paul's theory, though a more deft and credible walk along the borderline of divinity and humanity, is itself as fabulous as the Phoenix. Even so, Paul's is a better idea than fully this and fully that.