no. its a literal real kingdom.
the kingdom of God that is within did start at pentecost.
but there will be a real kingdom to fulfill the ot prophecies and acts 1:6
It is a literal real kingdom, as you say. But it will never be a "material/visible" kingdom on planet earth.
yes, the kingdom that is within did start at Pentecost.
Acts 1:6, the kingdom was restored to Israel on Pentecost. Then they rejected the covenant 3 1/2 years later and the gentiles entered in.
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Heb 13:14, "For here we have no continuing city, but we seek one to come."
The city that we seek is the heavenly one. The cities on planet earth are temporal, material, not continual.
So if we are seeking the one that is not continual (an earthly Jerusalem), aren't we going against what Paul said to seek, look for?
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We won't be returning to the old covenant with it's material services in a man made temple.
Heb 9:1, "Then verily the first covenant had also ordinances of divine service, and a worldly sanctuary."
But there are some, who love this world and want to stay here forever, and continue to live after the flesh, they want this world to be heaven, their heaven.
They don't trust Jesus enough to let go completely, everything material, this world is deteriorating to an end.
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Jesus rules from the heavenly Jerusalem now.
It is the eternal throne of David in heaven that Jesus is sitting on right now, it is the eternal throne in heavenly Jerusalem that lasts forever.
Jesus is sitting on it right now, ruling the kingdom on planet earth.
Don't look for the temporal city of Jerusalem on planet earth to have the eternal throne.