“He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.” (Lk.1:32-33) These are the words of Gabriel to Mary, the mother of Jesus.
Materially, David’s throne is no longer. Around 586 BC, Jerusalem was destroyed by Nebuchadnezzar; the temple and palace (with its throne) were brought to rubble. Also, the throne, as a by-word for the right of succession, was ended by the Lord; “O earth, earth, earth, hear the word of the LORD. Thus saith the LORD, Write ye this man childless, a man that shall not prosper in his days: for no man of his seed shall prosper, sitting upon the throne of David, and ruling any more in Judah.” (Jer.22:29-30)
The house of Jacob is not sequestered to an earthly, national identity. “Who shall ascend into the hill of the LORD? or who shall stand in his holy place? He that hath clean hands, and a pure heart; who hath not lifted up his soul unto vanity, nor sworn deceitfully. He shall receive the blessing from the LORD, and righteousness from the God of his salvation. This is the generation of them that seek him, that seek thy face, O Jacob. Selah.” (Ps.24:3-6)
What kingdom on earth can be unending? Hear the words of the Preacher; “I have seen all the works that are done under the sun; and, behold, all is vanity and vexation of spirit. That which is crooked cannot be made straight: and that which is wanting cannot be numbered.” (Eccl.1:14-15)
Therefore, Gabriel’s words can only make sense for a spiritual kingdom. As Jesus said; “The kingdom of God cometh not with observation: Neither shall they say, Lo here! or, lo there! for, behold, the kingdom of God is within you.” (Lk.17:20-21)