From the sermon: "The council of Nicaea in the year 325 determined that Jesus Christ was “God of God, Light of light, begotten not created” ... The Council of Nicaea taught us that Jesus was not just “like” God; he was God. He was “begotten, not created.” That is the one and only way that Jesus is not like us. He became one of us, and he was like us in every respect but this one: He was not “created” like us. He was “begotten” of the Father “before all worlds” and therefore “of one substance with the Father.”"With just this information, the questions arise: "God from God... begotten, not made." So was Mary simply a surrogate - carrying a child not of her body? Is this the reason that Mary is so revered by Catholics, that God provided only half of what begat Christ, and Mary provided the human half? If, as the Nicene Creed would indicate, Christ is begotten, He would not actually have been considered "human" per se, but rather went through the human experience without actually being human.
And yet, we know that Jesus was both fully human and fully God. Fortunately, these questions were answered long ago. Tom pointed out: the Definition of Chalcedon (451) comes in, to answer just those sorts of questions that were raised in the post-Nicene years: – as God the Holy Trinity is one divine Nature in three distinct Persons, so Christ is one Person in two Natures, fully human and fully God:
"truly God and truly man, consisting also of a reasonable soul and body; of one substance (homoousios) with the Father as regards his Godhead, and at the same time of one substance with us as regards his manhood; like us in all respects, apart from sin; as regards his Godhead, begotten of the Father before the ages, but yet as regards his manhood begotten, for us men and for our salvation, of Mary the Virgin, the God-bearer (Theotokos); one and the same Christ, Son, Lord, Only-begotten, recognized in two natures, without confusion, without change, without division, without separation; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and subsistence."The Definition was adopted in response to two extreme positions: the Docetist position, which was that Christ was basically an avatar, not really human but only seeming to be; and the Adoptionist position, that Christ was in fact a human being "adopted" by God to be His Son. Chalcedon affirmed that, no, he really is both fully human and fully God; the two natures, Divine and human, subsisting within one Person without division or confusion: because he was fully man, he truly lived and died as one of us, yet without sin; because he was also fully God, he sanctified and redeemed that humanness that he experienced – including death, but, again, excluding sin.
For us, accepting the Trinity on faith will also allow us to accept the duality of the nature of Christ in the same manner. This is likely why Rutledge explained that this is Christmas for grown-ups, but if we used the universal language of math, it's equally as easy to explain to a child: multiplication shows that 1x1x1=1. Three separate numbers, yet only one whole. Or in science, the states of being of H2O - steam, water and ice - three states, one substance. The duality of Christ can be exemplified in the same way - and what can be such a complex and never ending exploration into the nature of God - can also be simplified so that even a child can comprehend.
Well, Merry Christmas, indeed!