I the LORD have called thee in righteousness, and will hold thine hand, and will keep thee, and give thee for a covenant of the people, for a light of the Gentiles; To open the blind eyes, to bring out the prisoners from the prison, and them that sit in darkness out of the prison house. Isaiah 42:6-7
It is the events included in 6-day creation that are essential for Christian theology.
I realize that intelligent and godly Christians hold to this model of Earth history. Nevertheless, many seem unaware of the actual events they must inevitably adopt when affirming a 13.8 billion-year-old universe.