David’s decision to move the Ark of the Covenant to his new capital marks a major spiritual and national turning point, driven by a desire to correct many years of neglect. The plan involves physically transferring the Ark from its current location and bringing it directly to the people, specifically to the city of Jerusalem [מצודת ציון, ביאור שטיינזלץ, מצודת דוד].
The primary goal of this relocation is to gather around the Ark with a massive crowd, thereby multiplying its honor. By choosing Jerusalem, a city with a large population, the Ark will finally receive the immense respect it was denied in the past [מצודת דוד].
This national event is necessary because the people had completely ignored the Ark and its related matters for a long time [ביאור שטיינזלץ]. This period of neglect is heavily tied to the reign of King Saul. During his rule, Saul severely damaged the honor of the Ark when he destroyed Nob, the city of the priests who performed the holy service [רד״ק, מצודת דוד]. This historic disregard for the Ark aligns perfectly with other accounts of Saul's life, which explicitly note his broader failure to seek God [רד״ק].