As I look into the mirror it shows me that I am getting older. Although I don’t feel much different than 10 years ago, the mirror does not lie. When Isaiah encountered the Lord, it was like looking into a mirror, but a mirror that showed how sinful and imperfect he was.
Isaiah 5:3 The angels were calling out to each other (in the presence of the Lord), “Holy, holy, holy is the Lord of Heaven’s Armies! The whole earth is filled with his glory!” 4 Their voices shook the Temple to its foundations, and the entire building was filled with smoke. 5 Then I said, “It’s all over! I am doomed, for I am a sinful man. I have filthy lips, and I live among a people with filthy lips. Yet I have seen the King, the Lord of Heaven’s Armies.” 
Part of the work of the Holy Spirit is to show us our sin. God does not do this to beat us down, but to make us aware of our condition and our need for Him. In Isaiah’s vision, God made Isaiah deeply aware of his sin. Isaiah was a prophet who used his voice to declare the words of God, but he sees himself as a person of filthy lips. He sees that he is full of sin and his words are contaminated with sin. He has offended the holiness of God. God broke through and gave him awareness of his condition. He sees his condition which began to set him on a new path.
Isaiah had pronounced six “woes” on the nation in the previous chapter. He had listed things that God would judge. These included materialism, drinking, defiant sinfulness, perversion of values, arrogant conceit, and injustice. Now Isaiah pronounces the seventh woe on himself and his sinful life.
What is the Lord making you aware of that He wants to change in your life? The good news is as we repent of our sin and turn toward God, He forgives our sins, gives us peace and sets us on a new path. Romans 2: 4 Don’t you see how wonderfully kind, tolerant, and patient God is with you? Does this mean nothing to you? Can’t you see that his kindness is intended to turn you from your sin?
To hear more about Isaiah, listen here: https://podpoint.com/light-of-christ-church-podcast/the-call-isaiah