1 Chronicles 13:9
And when they came unto the threshingfloor of Chidon, Uzza put forth his hand to hold the ark; for the oxen stumbled. And when they came unto the threshingfloor of Chidon, Uzza put forth his hand to hold the ark; for the oxen stumbled.
The procession reached the threshingfloor of Chidon when the oxen stumbled, and Uzzah put forth his hand to steady the ark. That ark was the symbol of God's presence, so to lay hold of it presumptuously was a grave violation of what God had declared sacred. For that act he was struck dead, as the next verse records.