Christian Existentialism is a philosophical system which is an existentialism take on Christianity. It is traced back to the works of 19th century Danish philosopher Søren Kierkegaard, who is considered the father of existentialism, and thus it could be argued that existentialism is fundamentally a Christian concept that later diverged into other forms (most notably, the atheistic philosophies of Friedrich Nietzsche and Jean Paul Sartre).
According to Christian existentialism, one must totally submit to God without reasoning, meaning that absolute faith is void of any philosophy and intellect, and which Kierkegaard termed as a 'leap of faith.' People have free will, and are thus fully responsible for their actions. Rational grounds for theology and the divine will do not exist. The true God is not that of theologians or philosophers. Wars prove that there cannot be a rational understanding of God and Humanity. A Christian must resolve within himself the notion that faith is a myth or mystery to the concept that it is reality and truth before they will allow themselves to have an understanding of salvation. It is impossible to understand Being and faith through reason.
Existential Christians do not believe that we have a soul before our birth, or that God has a plan for us all. Instead, who we are is defined at birth, and that throughout our life that our personal relationship with God is what defines our life.
In this view, the Bible is not seen as an objective instruction manual, but as a personal guide for our life. The stories of the Old and New Testement both hold meanings, but these meanings are to be discovered and interpreted by each individual.
Kierkegaard himself was highly critical of the Church, and thought that it had distorted the teachings of Christ. Instead of focusing on the life of Christ, and teaching people how to live like Christ, it taught a highly dogmatical view of Christianity which it expected people to live by. He and other Christian existentialists believe that people must form a personal relationship with God and Christ by themselves and believe and practice Christ on their own terms.