Matthew Henry Commentary 2 Samuel 6:6-11

"And when they came to the threshing-floor of Nacon, Uzzah put forth [his hand] to the ark of God, and took hold of it; for the oxen stumbled. And the anger of Jehovah was kindled against Uzzah; and God smote him there for his error; and there he died by the ark of God. And David was displeased, because Jehovah had broken forth upon Uzzah; and he called that place Perez-uzzah, unto this day. And David was afraid of Jehovah that day; and he said, How shall the ark of Jehovah come unto me? So David would not remove the ark of Jehovah unto him into the city of David; but David carried it aside into the house of Obed-edom the Gittite. And the ark of Jehovah remained in the house of Obed-edom the Gittite three months: and Jehovah blessed Obed-edom, and all his house." — 2 Samuel 6:6-11 (ASV)

Uzzah was struck dead for touching the ark. God saw presumption and irreverence in Uzzah's heart. Familiarity, even with that which is most sacred, tends to breed contempt. If it were so great a crime for one to take hold of the ark of the covenant who had no right to do so, what is it for those to lay claim to the privileges of the covenant who do not meet its terms?

Obed-edom opened his doors without fear, knowing the ark was a savour of death unto death only to those who treated it wrongly. The same hand that punished Uzzah's proud presumption rewarded Obed-edom's humble boldness. Let no one think worse of the gospel because of the judgments on those who reject it, but consider the blessings it brings to all who receive it.

Let heads of households be encouraged to maintain religious practice in their families. It is good to live in a family that welcomes the ark, for everyone in it will fare better.