Concept:Isaiah stresses God’s holiness because God Himself, who called Isaiah, is completely holy.
Explanation:In Isaiah’s vision (Isaiah 6:1–8), the seraphim cry out: “Holy, holy, holy is the LORD of hosts.”
This threefold repetition shows that holiness is the very heart of God’s character.
Because God is holy, He calls His people to live holy lives.
So the main reason Isaiah emphasized holiness is not about sacrifices, hearts, or sin alone.
It is that the God who called them is holy and demands holiness from them.
Therefore, the correct option is the one that points to God’s holy nature.
Answer:C. who called them is holy