Bringing the Ark of the Covenant to Jerusalem is marked by an extraordinary display of spiritual passion and humility from the King of Israel. At the height of the celebration, David abandons standard royal etiquette to express immense joy and complete submission to God. He does this first through physical movement, performing a dance of pure joy [רש״י, מצודת ציון]. He dances with all his strength, focus, and enthusiasm, holding nothing back in quiet restraint [מצודת ציון, רד״ק, ביאור שטיינזלץ]. Taking the role of the main celebrant, David chooses to dance alone, setting himself apart from the rest of the nation. This is a notable shift from his first attempt to bring up the Ark, where he simply blended in as part of the celebrating crowd [אברבנאל, ביאור שטיינזלץ].
Alongside his physical devotion, David completely changes his attire, wearing a linen ephod, which is described as a coat made of fine linen or a type of skirt [רש״י, ביאור שטיינזלץ]. While this garment looks similar to the ephod worn by the High Priest and is specially worn by those dedicating themselves to serving God [מצודת דוד, אברבנאל], it is not the official, exclusive priestly clothing mentioned in the Torah. Rather, it is a garment of honor that anyone, even a person who is not a priest, is permitted to wear while engaged in holy service [רד״ק].
The central theme of David's actions is the complete surrender of his personal honor in the face of God's glory. The primary approach among commentators is that David purposely leaves his royal robes behind. Instead, he wraps himself in a simple linen ephod to look like an ordinary servant of God, ensuring no display of pride. Precisely because of his high position as king, he feels a much deeper duty to show absolute submission before the Creator. He expresses this letting go of his ego on two parallel levels: through his body, by dancing and running with all his might, and through his clothing, by trading the symbols of his power for the simple dress of spiritual service [מלבי״ם, ביאור שטיינזלץ].