As Isaiah is called to be a prophet, he has a vision. We can read about it in the verses before the one above. When Isaiah came face to face with the Lord, he realized that he was a sinner. He realized that the Lord is holy and perfect. He knew that he was not worthy to speak to the Lord because of his sinfulness. If we are familiar with this section of scripture, we know that a seraphim flew to him and placed a hot coal in his mouth, saying, “Your iniquity is taken away, your sin purged.”
Isaiah had it right. We can’t just come to the Lord on our own. We need to have our iniquity taken away and our sins purged. God is Holy and we can’t approach Him any other way. The good news is that He sent His Son to die on the cross for our sins. Because of this, He casts our sins as far as the east is to the west (Psalm 103:12). We can now come boldly into the throne of grace (Hebrews 4:16).