They brought in the ark of God, and set it in the midst of the tent that David had pitched for it: and they offered burnt offerings and peace-offerings before God.
These verses actually belong to the record of bringing the ark into Jerusalem in the previous chapter.  "They make it clear that the sacrifices were presented by the whole community of Israel with the Levitical priests performing their proper functions.  David appears here, not as a priest, but as the king who supervised the proper activities of worship."[1]