And yet Jesus always was.
John 8:58: Jesus declared, "Very truly I tell you, before Abraham was born, I am!"
"Flesh" means humanity, not that he didn't have a human body before hand and suddenly, now he does. Other wise, how are we made in His "image"?
Also, its your argument about everything old = truth. My argument is wisdom/discernment is needed and truth is dependent on what is actually true, and not just because it's old.
The Second Person of the Trinity, the "I am" of John 8:58, is Eternal--the Son, the Logos, has always existed because He's God. As the Nicene Creed states, He is "begotten of the Father before all ages" "begotten, not made" "of the same Being with the Father". As the Divine Son He is Eternal God, consubstantial with the Father.
That Hypostasis, that Person, the Son/Logos, at a specific point in time became flesh--became human--of the Virgin Mary.
"But when the fullness of time had come, God sent forth His Son, born of woman, born under the law." - Galatians 4:4
In this way the Logos "became flesh and dwelt among us" (John 1:14)
God became man.
This is the Incarnation. God the Son united to Himself human nature, and in so doing received a human body and soul. As we confess in the Symbol put forward at Chalcedon, He is "fully human, of a rational soul and body".
So that Jesus Christ is to be confessed as One Person, undivided; both fully human and fully Divine; with neither confusion nor separation. We do not divide the Person, so as to deny that it is truly God who was conceived and born of the Virgin Mary; nor do we confuse the "natures" so as to eradicate the distinctiveness of each--for we confess that the Son suffered not in His Divinity, but in His humanity, and yet as the Acts of the Apostles tells us, the Church is founded on God's own blood.
He was conceived by the power of the Holy Spirit in the womb of the Virgin Mary, as true flesh of her flesh, like us in all ways but without sin. Truly human. Remaining, however, as He always was: True God, consubstantial with the Father, only-begotten Son, the Logos.
The idea that God, in His Essence, has physical form--a body--is an age old heresy called Audianism. Audius taught, wrongly, that the Divine Essence had physical form, and that when Genesis it says humans are made in the Image of God it means
physically. This view is, through-and-through heretical.
God does not have shape nor form, He is God.
God the Son, in His Incarnation, has a human body--
because He's human.