The ark of the covenant of the Lord reappears. Remember, this is considered the actual presence of the Lord, it is that which had to be revered and had been residing in David's priest's town Kiriath-Jearim, or as this Scripture states Baale-judah, under the watch of Abinadab. We haven't seen him for a while or heard about the ark for a while. Glad that they are both doing well. David realizes that he is now settled and it is time for him to get the Lord back into his home so that he doesn't have to travel as far to worship God. Let's bring the presence of the Lord home to Jerusalem.
They start the trek with much singing and dancing and things are just going great, until they aren't. The ark gets jostled a bit and one of David's men reaches out to steady it. Apparently you don't touch the ark, we should have known this, and God strikes down the man who touched it. David sulks and decides that he doesn't want to have the ark in his house after all and goes home and leaves the ark there.
No, seriously, that is what happens. Like a middle school boy who wasn't allowed to play, he leaves and goes home and sulks...until...he hears that the place where he left it, and the family with whom he left it, are being blessed abundantly by the Lord because, well, God is present wherever the ark is present. This took place over three months before David realized he better go claim the ark for himself again.
He does so and as he is bringing the ark into Jerusalem he strips off his clothes down to his tidy whiteys and starts dancing before God so that God would be pleased. He was making a fool of himself, but he didn't care, he just wanted the Lord to know that he loved Him and was celebrating His presence. He was dancing as if no one was watching.
Well, his wife, the daughter of Saul, his oldest wife, was watching and she did not approve. Everyone is going to think that you are a fool. You are the only one who thinks that I am a fool, everyone else knows who I am, what I have done, and respects me for it. The Scripture ends with a foreboding sentence that Michal, the wife who disapproved, did not have children for the rest of her life. So now David has a home and has God living in his home and things can only get better.