We have seen that God is holy in His distinctiveness from His creation. We know that He sets us apart for Himself, and this is not something we take for granted. God is not just holy in His being, but He is ethically holy. That is, He is pure of all sin while we, on the other hand, are filled with sin (Romans 3:10-18).
The first words Isaiah utters upon seeing the Lord are, “‘Woe to me! … I am ruined! For I am a man of unclean lips, and I live among a people of unclean lips, and my eyes have seen the King, the Lord Almighty’” (6:5). He was profoundly aware of his disgrace before the pure, sinless, holy God.
God’s holiness has us in the same place as Isaiah: realizing our ruin because of our sin and brokenness. But He doesn’t leave us there. Just as God’s holiness led to Isaiah’s sin being atoned for (v. 6), so it is with us. Then Isaiah was set apart for God’s message (v. 8-13). If that is the pattern, it’s no surprise that Jesus is our holiness (1 Corinthians 1:30) who then brings us into His mission.