Yeah, rather than thinking about it and believing it, just shove it into the 'all fulfilled in Christ' drawer and forget about it.
Then, you don't have to deal with it.
God loved Abraham because he had faith and obeyed everything that God said.
So God promised that Abraham's children, grandchildren, great grandchildren, their children, on and on...that those blood related to Abraham, from that blood line, the Savior of the world will come.
Now that Jesus has come, only his blood matters.
All things are now of Jesus Christ; all things on earth, all things in hell/prison, meaning things past that lived before, all things in heaven and all things that will come to life in the future. Jesus is before all. Jesus is above everything. Since Jesus, all must go through Jesus to be saved.
When Jesus came and died for the whole world, it was no half completed failed mission to be continued at a later date.
Jesus never came to live on this world as an earthly King. Eh, really? Do you really want to believe that this world was something to be desired to live on and rule? No. Jesus came to save us from this evil world. He came to teach us about his world, what was spiritual, what was of God. One day there will be a new earth, and not like this decaying earth, this decaying earth that you have the audacity to think Jesus wanted to live here. It is as if you think it is something to be desired, to live here and be King as opposed to being King over the whole universe, the earth included.
When Jesus came, he tore down the veil of the old law, and he tore down the dividing wall, the wall that divided people by blood and by purity; The wall that separated the chosen Jews, from the uncircumcised...that way is gone. We are all alike and all condemned. We must all come to God the same way, no blood relative of Abraham has a better promise. No blood relative of Abraham is blessed just because of Abraham. No blood relative of Abraham has another chance later. All have the same chance now.
The old law has faded away.
No one can even do any of the old law anymore.
During the time of the apostles, the old law could still be followed, for there was an earthly temple and an earthly priesthood, and the pharisees and teachers of the law enforced it.
Jesus said it would be destroyed.
It has been destroyed.
To be built again is to blasphemy God, for God's temple is Jesus Christ, and all those who believe in Jesus.