2 Samuel 7:15

But my mercy shall not depart away from him , as I took it from Saul - His house shall be a lasting house, and he shall die in the throne of Israel, his children succeeding him; and the spiritual seed, Christ, possessing and ruling in that throne to the end of time.

The family of Saul became totally extinct; the family of David remained till the incarnation. Joseph and Mary were both of that family; Jesus was the only heir to the kingdom of Israel; he did not choose to sit on the secular throne, he ascended the spiritual throne, and now he is exalted to the right hand of God, a Prince and a Savior, to give repentance and remission of sins. See the observations at the end of the chapter, 2 Samuel 7:25 ; (note).

Many have applied these verses and their parallels to support the doctrine of unconditional final perseverance; but with it the text has nothing to do; and were we to press it, because of the antitype, Solomon, the doctrine would most evidently be ruined, for there is neither proof nor evidence of Solomon's salvation.