3. One of the preparations for prophecy is seclusion; generally, that is practiced outside a city. David made his primary preparations for prophecy while he was on the way to, but still outside the City of David. Accordingly, the narrative relates that there, he was wearing a linen ephod.
This also explains [why he was] "dancing with all his might before G-d," since "the Divine Presence rests only amid joy." Also, the term mecharker, translated as "dancing," also means "praising." David was reciting psalms and praises to G-d to elicit the revelation of prophecy, for praises and laudations evoke Divine potentials that are usually hidden, too sublime to be revealed, as is well known.
When describing the joy in the City of David, the text also mentions that David was "leaping," indicating exuberant dancing. Outside the city, his dancing was not exuberant; possibly he did not dance at all. As explained in Chassidus, dancing stems from joy permeating the person thoroughly, to the extent that it affects even the feet.
That is why the term "leaping" is mentioned specifically in the second verse. David’s joy outside the city had a specific purpose; he sought to elicit prophecy, that the Divine Presence would rest upon him. Since his joy had a purpose and a goal, it was limited and did not permeate him entirely. In the City of David, by contrast, his joy had no ulterior motive and, consequently, was unlimited. As such, there, he was also "leaping."
