1Chronicles 13:9-10 And when they came unto the threshingfloor of Chidon, Uzzah put forth his hand to hold the ark; for the oxen stumbled. 10 And the anger of the LORD was kindled against Uzzah, and he smote him, because he put his hand to the ark: and there he died before God.
Here is a note on this incident from the Treasury of Scripture Knowledge by R.A. Torrey:
Even the Kohathites, who were appointed to carry the ark, after it was covered by the priests, were forbidden to touch it on pain of death; but Uzzah, who certainly was no priest, probably with some degree of irreverence, having presumed to lay his hand upon the ark, which perhaps was not covered, thus incurred the penalty due to his rashness. See Numbers 4:15 - 20
Uzzah's example is very profound in teaching us about our relationship to God. An ignorant or irreverent approach to God will not be tolerated. There is no excuse for either lack of understanding or irreverence in our approach to the LORD of the universe who has also deigned to be called our Father. The fact that we understand the Fatherhood of God should not be used as licence for disrespect or lack of appropriate reverence.
I hope you have found this helpful.