On the contrary. Samuel tells us that Jesus is David's own flesh and blood, which implies that God did not form a new seed for Mary but literally took the seed of David, which did not exist before David himself existed.
We might say it’s
implied, but it’s not
explicit and the Bible argues very strongly against that idea. For example, we know that the genealogies trace Christs lineage back
before David (Luke 3:23-38,) so the idea that there’s no chance of Jesus existing before Davids seed can’t be defended.
In addition we know Jesus doesn’t have Davids
own blood or flesh inside of Him, we have to interpret that in an
idiomatic sense every time.
Though the point about preexisting apart from the
seed idea would be covered by my writing
“in essence,” Spirit. We might write David, Solomon or Christ
“died,” but by an orthodox Christian reckoning the most
essential thing isn’t someones body but their soul.
King Davids soul doesn’t predate his earthly body, Christs soul or His consciousness does preexist beyond His human body however, that’s according to both Christianity and the Watchtower
(either as the Word or in an angelic fashion.)
The
“seed” isn’t meant to be used in scripture as a strict biomedical term
(e.g. 1 John 3:9,) but rather it’s used to say someone belongs to or is in the lineage of someone else, that
might be with regards to the physical seed, but occasionally it’s not.
Even Onans feared his
“seed” wouldn’t be his
seed so he spills his own
seed upon the ground
(Genesis 38:9,) it’s simply not a straightforward word.
For another example, if it’s just to do with physical lineage, Mary is in the
lineage of David, but there’s no
“seed” there for her to pass onto Christ as if it were Onan in Genesis, that’s not possible in classical Jewish thought.
The
“seed of the woman” crushes the serpents head in Genesis
(Genesis 3:15,) but that’s not related to anything in female biology. Actually the verse is nearer to your idea that God shared a whole other seed with the woman
(since female seed makes no physical sense.)
Another example of the legalistic kind, Jesus’ genealogy argues for His
lineage through Joseph, and that’s considered valid to the biblical audience, at the same time, everyone reading accepted that Joseph wasn’t the biological father of Jesus.
In the same way writing the Word became flesh isn’t to say that the Word picked up another
essential thing so as to change themselves on the level of Spirit, their Spirit remains their own regardless of the physical body or it’s status.
Otherwise you would have to claim that Jesus is the word only, and not the flesh and blood man at all, but if that were so scripture would not refer to him as "the son of man", and neither would he have actually died because the word can not die, only flesh, but he is the son of man, and he did die, and therefore we must agree that the flesh and blood, which has not always existed, is Jesus.
I think this is another example of where the biblical writers distaste for articulating themselves in minute exactness gets whipped up into something of a storm in a teacup, like in the case of creating
through versus creating
by.
Think of it this way, the biblical writers didn’t really seem to care about making distinctions to do with
when sonship occurred, we know this because the Bible authors reference
the Son Jesus or the firstborn
(implying sonship) but then they proceed to write about things far in advance of His physical birth to Mary
(Hebrews 1:8-10.)
In reality what we describe as the
essentials of who we later name Jesus clearly preexisted the physical body of Jesus in both historic Christianity and in the views of the Watchtower society. So arguing that Jesus doesn’t preexist because His body didn’t exist or because the seed wasn’t made really isn’t in line with how the biblical writers thought.
The biblical authors thought of Jesus’ existence being long before what we would call His essence appearing as a man, much in the same way as how they predate
the Fathers existence while He appears to have manifested Himself in human form somehow
(Genesis 18, Genesis 19, Exodus 24:9-10.)
Moses and Aaron, Nadab and Abihu, and the seventy elders of Israel went up and saw the God of Israel. Under his feet was something like a pavement made of lapis lazuli, as bright blue as the sky.
What’s true of the Son is true of the Father. The Bible writers unabashedly attach titles like
“The Son,” firstborn or the name Jesus onto Christ before His appearance as a physical man
(Philippians 2:5-6, Hebrews 1:6.)
They write this way regardless of when the body was made or when sonship occurred, or as Jesus casually spoke in the gospel of John
(John 17:5.)
Now, Father, glorify Me together with Yourself, with the glory which I had with You before the world was.