If your children will keep my covenant and my testimony that I shall teach them, their children shall also sit upon your throne forevermore.
Read Chapter 132
Augustine of Hippo
AD 430
12. What then? "The Lord hath made a faithful oath unto David, and He shall not shrink from it; Of the fruit of thy body shall I set upon thy seat. If thy children will keep My covenant and My testimonies that I shall learn them, their children also shall sit upon thy seat for evermore" (ver. 12). If thy children keep My covenant, their children also shall sit for evermore. The parents establish a desert on behalf of their children. What if his children should keep the covenant, and their children should not keep it? Why is the happiness of the children promised in relation to their parents' deservings? For what saith He, "If thy children will keep My covenant, their children also shall sit for evermore"-He saith not, if thy children keep My covenant, they shall sit upon thy seat; and if their children keep My covenant, they also shall sit upon thy seat: but he saith, "If thy children keep My covenant, their children also shall sit upon thy seat for evermore"-except because He here wis...
If. The promises made to the carnal posterity of David were conditional, and seem to imply, that they would forfeit them. (St. Hilary)
But those regarding the Messias are absolute. (Calmet)
Yet heaven is only promised to his children in the Church, if they observe God's commandments, Romans viii. 17. (Worthington)
The kings of Juda seem not to have believed these threats; and many Christians live as if heaven required no conditions on their part. God knew what would be the event; but he speaks thus to testify their free-will, and his desire to preserve the temporal throne of David, at least till the coming of the Messias, if the Jews had proven faithful. (Berthier)