“The second half of 2 Samuel 6 records the removal of the ark to Israel in observance of the ‘proper order.’ The Levites carried it, according to the commandment of the Lord, and we are also told that David in his enthusiasm ‘danced before the Lord with all his might.’ This dancing, combined with the fact that David discarded his kingly robes and stripped down to a linen ephod for the occasion, incurred the scorn of his wife, Michal, who chided him for his indignity. David responded to her contempt by pointing out that he danced and played ‘before the Lord.’
There are some who cite this passage as a justification for the use of all kinds of musical instruments in the worship of God, since David says, ‘I will play before the Lord.’ A few observations, however, show this argument to be without merit.
1) The word ‘play’ used here does not necessarily require musical instruments. It simply means ‘to laugh; or, to make sport,’ and is an apt description of David's joy.
2) There is a contrast in the chapter itself between the employment of ‘all kinds of instruments’ (verse 5) during the first unsuccessful attempt to move the ark, and the simple ‘sounding of the trumpet’ (verse 15), presumably by the priests in accordance with Numbers 10 on this occasion.
3) The argument proves too much, since it would also require the people of God to ‘dance with abandon’ in public worship in their skivvies, of which there is no hint of approval in all of the Scriptures.
The point to be taken from David’s dancing is that his enthusiasm was the natural expression of the joy that filled his heart at the sight of the return of God's ark to its rightful place.” (Comin, 90-91)