Isaiah emphasized holiness above all things because God

Isaiah emphasized holiness above all things because God who called them is holy. Isaiah recognized that God was the one who called the people of Israel, and He is holy. Therefore, to be in a right relationship with God, they had to pursue holiness. God's holiness was incompatible with sin, and if they wanted to have a relationship with Him, they needed to live in obedience to His commands and strive for holiness in their lives. Isaiah wanted the people to understand that God was not interested in their sacrifices, but He desired their hearts to be pure and holy. Therefore, they had to pursue holiness, which was the only way to be in a right relationship with God.