“the Levites bore the ark of God on their shoulders, by its poles, as Moses had commanded according to the word of the Lord” (1 Chronicles 15:15 NKJV)

David’s first attempt at transporting the ark to Jerusalem failed when Uzzah was struck dead by God while reaching out to steady the ark when the oxen pulling the cart stumbled. David became so afraid of God that they left the ark there. But after a season, David researched this with the Levites and discovered that he had not followed God’s instructions for carrying the ark. It was not to be carried by oxen and cart. It was to be carried by men, specifically, set-apart men from the priestly house of Levi. And they were to carry it in a very specified way- “with the poles on their shoulders.” They were to carry it with their faces towards the ark and the backs towards the world, being careful not to touch it, but to honor it and not let it fall.
David learned to follow God’s Word in how he worshiped. How we worship matters to God.