1 Chronicles 13:10
And the anger of the LORD was kindled against Uzza, and he smote him, because he put his hand to the ark: and there he died before God. And the anger of the LORD was kindled against Uzza, and he smote him, because he put his hand to the ark: and there he died before God.
Uzza was struck dead for laying his hand upon the ark while it was being carried up to Jerusalem. The ark was the symbol of God's presence among His people. To lay a hand upon it was a presumptuous act in violation of what God had declared sacred.