The Ark is safely in a tent, but David's feeling a little guilty. So he calls on his prophet/friend Nathan to join him.
David tells Nathan that it just doesn't seem right. After all, David lives in a nice house made of cedar wood and God's just hanging out in some old tent.
Later, God tells Nathan to let David know that he doesn't mind their living arrangements. He's been there since he freed the people from slavery back in Egypt. He's got no problem with roughing it.
God says that he made David king and he'll watch out for him. He'll give the people a permanent home where no one can bother them or throw them out (good luck with that, God).
He's also going to take one of David's sons and make him a king, too. This son will build a temple to God and that will make the Almighty very happy.
In return, God will love this son forever. Oh, who could it be?
Naturally, David's grateful to God for all the blessings he's promised him. He's just one lowly king and God is the Creator of Heaven and Earth. David's pretty humbled to be singled out for special treatment.
David really hopes all this will come to pass. God will have a house. Israel will be safe. And everyone will praise God forever. It's a win-win-win.