The ark was not carried the proper way the first time. It was placed in a cart drawn by oxen. Uzzah put out his hand to steady it when the oxen stumbled but God struck him dead in anger. Why? Numbers 4:15 explains that while the sons of Kohath could the furnishings of the sanctuary–the things in the Tabernacle of Meeting, but they could not touch any holy thing or they would die. Uzzah died because he touched the ark. He acted impulsively and it cost him his life.
Verse 13 says that there were those bearing the ark of the Lord. Who bore the ark this time and in the proper way? We read this in 1 Chronicles 15:12-15. David acknowledged that they did not consult God about the proper procedure for carrying the ark. The Levites were to bring up the ark. They were to sanctify themselves and their brethren. So, the Levites sanctified themselves so that they could bring up the ark of the Lord. They bore the ark on their shoulders by its poles as Moses had commanded according to the word of the Lord (verse 15, Exodus 25:14).
God had told His people through Moses the proper way to carry the ark and had they done as instructed, Uzzah would not have been struck down.
We must always do things the way God tells us to do them instead of doing them our way. Going against God’s wishes or failing to follow His instructions can have serious, even fatal repercussions as David learned.