The passage relays the vision Isaiah had of God on His throne and the coming of the atoning work of Christ at Calvary. It's a splendid and bold declaration of God's power over creation and His saving power over humanity. The creatures in heaven are singing praise about the perfect holiness of God. Holiness might not be a word we hear in many churches today. We are told by culture, the media, and even some Christian churches that "tolerance" is a far better attribute than holiness.
The Reformed theologian R.C. Sproul declared that the entire focus of his ministry was to awaken people to the holiness of God. If we don't see the majestic holiness of God we have a harder time being aware of our own sin and our need for repentance. The more we seek after God and conform to his image the more we are aware of the difference that lies between God's goodness and our own.
Holiness is God's infinite goodness. There is nothing the Lord doesn't do that isn't perfect and morally just and right.
Much of our culture and entertainment industry focuses on our happiness and even many churches preach that our goal is one of happiness. But holiness comes first. If we want the real presence of joy, it cannot come to us without being holy.
What the prophet Isaiah saw in this passage is that he was vastly unclean to stand in the presence of God and he was overtaken by God's perfection and goodness. He also saw a glimpse of the coming of John 3:16, "For God so loved the world that He gave His only begotten Son so that whoever shall believe will not perish but have eternal life." Isaiah 6 is a picture of the Gospel of Jesus Christ.
When we start to see our actions and sin measured against the Holy God, we realize our desperate need for forgiveness and reconciliation. We also see the need to better reflect the image of God and His character as best we can. Today, the world will continue to chase after and glorify a detached worldly happiness that focuses on the individual person. But it's much better to be like Isaiah and be overwhelmed by the holiness of God. When we start to feel like Isaiah, we demand so much better. It is only through Jesus Christ where we truly find holy love that not only fulfills us, but cleanses us from the emptiness the world and sin promises us.