Albert Barnes Commentary 2 Samuel 6:16

"And it was so, as the ark of Jehovah came into the city of David, that Michal the daughter of Saul looked out at the window, and saw king David leaping and dancing before Jehovah; and she despised him in her heart." — 2 Samuel 6:16 (ASV)

She despised him in her heart - In the days of Saul the ark had been neglected (1 Chronicles 13:3), and Saul had in everything shown himself to be an irreligious king. Michal seems to have been of a similar spirit.

The whole section, 2 Samuel 6:16-36, should be compared with 1 Chronicles 15:29 and 1 Chronicles 16:43.

The peace offerings were made with a special view to feasting the people (compare to 1 Kings 8:63–66).