1 Chronicles 28:5
And of all my sons, (for the LORD hath given me many sons,) he hath chosen Solomon my son to sit upon the throne of the kingdom of the LORD over Israel. And of all my sons, (for the LORD hath given me many sons,) he hath chosen Solomon my son to sit upon the throne of the kingdom of the LORD over Israel.
Israel's throne is the kingdom of the LORD, for the Lord God of Israel, ruler of all the world, reigns over Israel in a theocracy. Of all David's many sons, the Lord chose Solomon to sit upon that throne and succeed David as king over Israel after David's death. That choice did not leave the work with David himself, but passed the kingship to Solomon as his successor. Solomon was David's son by Bathsheba, who kept the love of God before him, and David recognized him alone of all his sons as qualified to rule the people.
Chosen as king meant also appointed to build God's house, the temple. David could gather materials for that house and put his experience at Solomon's service in counsel and encouragement. But the work assigned to Solomon had to be carried out by Solomon himself, by the younger man, and could not be done by another in his place.
God joined to this choosing a promise to establish Solomon's kingdom forever, on condition that he remain faithful and obedient to God's commandments and judgments. To be chosen to lead God's kingdom in this way lays sacred responsibilities upon the leader. It requires dependable character and fitness to serve a people set apart for God.