In this chapter, you begin to see why it is that Jesus comes from the line of David. David wanted to bring the ark of God into his palace, and Nathan the prophet said that it wouldn't be wrong if he did this, because the Lord showed David favor wherever he went. Nathan receives a vision from the Lord in which David's house would be blessed for generations to come.
Listen to what David says in response to how God would bless his rule:
And now, Sovereign Lord, in addition to everything else, you speak of giving your servant a lasting dynasty! Do you deal with everyone this way, O Sovereign Lord?
“What more can I say to you? You know what your servant is really like, Sovereign Lord. Because of your promise and according to your will, you have done all these great things and have made them known to your servant. (v. 19-21)
You can see why God chose to use David as the line from which the Messiah would come.
GRACE AND PEACE!