The Throne of David

 Luther and Calvin got some things right. Eternal life is a free gift from God. We cannot earn salvation through works.

For by grace you have been saved through faith, and this is not your own doing; it is the gift of God—
not the result of works, so that no one may boast. Eph 2:8–9 NRSV

But in one area they went right off track.

Luther and Calvin did not understand that God would restore the Jewish nation in the future.

When the archangel Gabriel visited Mary, he spoke of Mary's calling to be the mother of God's Son. Gabriel also declared the following promise about Jesus:

He will be great, and will be called the Son of the Most High, and the Lord God will give to him the throne of his ancestor David.
He will reign over the house of Jacob forever, and of his kingdom there will be no end.” Lk 1:32–33 NRSV

David never had a throne in heaven, only on earth in Jerusalem. When Jesus of Nazareth lived his earthly life, he never sat on a throne. Jesus has a throne in heaven but it is not David's throne, because David is only a man and in heaven only God sits on the throne.

When and where will Jesus sit on David's throne? It must be after his promised return, and it must be in Jerusalem. Otherwise this promise in Luke is totally meaningless, illogical and impossible.

We read here that Jesus will sit on David's throne and that he will reign as King of the Jews. The house of Jacob means the Jewish nation.

Luther and Calvin have misguided Christians.

When biblical prophecies declared a future for Israel or Jerusalem, they taught that God was not really speaking of the Jews, but of the Church. According to Luther and his followers, Israel and Jerusalem were only symbols for the church.

As for those who will follow this rule—peace be upon them, and mercy, and upon the Israel of God. Ga 6:16 NRSV

Many understand these words ‘the Israel of God’ as an allusion to the Church. That is perhaps possible. But then they go much further and claim that many unfulfilled prophecies about Israel, Jerusalem and the Jews no longer apply to the Jews.

But Paul teaches quite clearly. This is not the case.

And so all Israel will be saved; as it is written, “Out of Zion will come the Deliverer; he will banish ungodliness from Jacob.” Ro 11:26 NRSV

Is Paul talking about the Christian church here? No. Who is ‘Jacob’? It can only be the Hebrew nation.
At the end of the Great Tribulation, Jesus will return from heaven. He will not appear anywhere on earth, but precisely in Israel.

That is why the restoration of the Jewish nation in Israel is so important, because Jesus will return to his own Hebrew people right there.
 
And I will pour out a spirit of compassion and supplication on the house of David and the inhabitants of Jerusalem, so that, when they look on the one whom they have pierced, they shall mourn for him, as one mourns for an only child, and weep bitterly over him, as one weeps over a firstborn. Zec 12:10 NRSV