2 Sam 6:6-9

But when they came to the threshing floor of Nacon, Uzzah reached out toward the ark of God and took hold of it, for the oxen nearly upset it. And the anger of the LORD burned against Uzzah, and God struck him down there for his irreverence; and he died there by the ark of God. David became angry because of the LORD'S outburst against Uzzah, and that place is called Perez-uzzah to this day. So David was afraid of the LORD that day; and he said, "How can the ark of the LORD come to me?" - 2 Sam 6:6-9

There is a strange trend in our generation to try to reduce role models and authority figures to normal people through mockery or acting like they are our best friends. We see this spill over into Christianity with the idea that Jesus is my best friend, for example. This idea turns the Creator of the universe and sustainer of all things into one of the dudes I play poker with every week while smoking a cigar or the girl I have a coffee and long conversations with. While Jesus is the lover of our souls and desires a real relationship with us, He is also the Holy God. Because of this, He desires us to be holy, as He is holy, and to respect Him for who He is. Uzzah was trying to do a good thing when he tried to stop the Ark of God from falling over, but he didn't honor the holiness of God by doing so. This is why God struck him dead. It seems harsh to us maybe, but we need to understand that God had given specific ways to carry the ark and to handle it with reverence. When the people failed to do that, He was gracious enough to allow them to continue, but when they stepped over the line, He had to act. Today, God often withholds His judgment of our sins because of His love, but we shouldn't expect Him to allow us to continue in an irreverent and unloving attitude with Him. He is a holy God and needs to be treated as such. We need to be close to God, but in His way and according to His terms. Then and only then can we be set free from fear and truly enjoy the love and grace of God.