23 We know then for certain that the Lord was to be born of a Virgin, but we have to show of what family the Virgin was. The Lord swore in truth unto David, and will not set it aside. Of the fruit of body will I set upon your throne: and again, seed will I establish for ever, and his throne as the days of heaven. And afterwards, Once have I sworn by My holiness that I will not lie unto David. His seed shall endure for ever, and his throne as the sun before Me, and as the moon established for ever. You see that the discourse is of Christ, not of Solomon.
For Solomon's throne endured not as the sun. But if any deny this, because Christ sat not on David's throne of wood, we will bring forward that saying, The Scribes and the Pharisees sit in Moses' seat: for it signifies not his wooden seat, but the authority of his teaching. In like manner then I would have you seek for David's throne not the throne of wood, but the kingdom itself. Take, too, as my witnesses the children who cried aloud, Hosanna to the Son of David, blessed is the King of Israel. And the blind men also say, Son of David, have mercy on us. Gabriel too testifies plainly to Mary, saying, And the Lord God shall give unto Him the throne of His father David. Paul also says, Remember Jesus Christ raised from the dead, of the seed of David, according to my Gospel: and in the beginning of the Epistle to the Romans he says, Which was made of the seed of David according to the flesh. Receive thou therefore Him that was born of David, believing the prophecy which says, And in that day there shall be a root of Jesse, and He that shall rise to rule over the Gentiles: in Him shall the Gentiles trust.
Source: Catechetical Lectures (New Advent)