Isaiah was considered the greatest Old Testament prophet. He had powerful messages of both judgment and hope.
God is purely and perfectly holy, and just, and loving.
In Jerusalem - Isaiah was a Scribe and Prophet.
King Uzziah died of leprosy for trying to take over the High Priest's duties. Although he was generally a good king and his reign was long and prosperous, many of his people turned away from God.
The lofty throne, the attending angels, and the threefold holy all stressed God holiness. We need to rediscover God holiness. We need the Bible's view of God as high and lifted us out of our problems and concerns.
Isaiah's vision was his call to be God's messenger to his people. Isaiah was given a difficult mission. He had to tell people who believed they were blessed by God that God was going to destroy them because of their disobedience.
The seraphims are an order of angelic beings created by God. Here they functioned as God's agents in commissioning Isaiah. Isaiah could understand them when they spoke to him and when they praised God. They were awe-inspiring and powerful creatures - their singing shook the Temple!
Listening to the praise of the angels, Isaiah realized he was common and unclean before God, with no hope of measuring up to God's standard of holiness. When his lips were touched with a burning coal, however, he was told his sins were forgiven. It wasn't the coal that cleansed him, but God. No matter how difficult his task would be, he said, "Here am I; send me." Before we accept God's call to speak for him to those around us, we must be cleansed as Isaiah was. Letting God purify us may be painful, but we must be purified so that we can truly represent God, who is pure and holy.
Reference summary used from the Life Application Bible; KJV, Tyndale Bible Publishers, Wheaton, IL