If existence is nausea then faith is an uncertain relief.
This is a response to Moses's reading of Pratt's short history of the Civil War and to Kierkegaard. He had been reading these books when he lived alone in Philadelphia and commuted to meet his son in New York; living in a state of depression. This response is important because, first of all, Moses does not say it with conviction, really, at this point in the novel. This uncertainty is not a positive thing for Herzog here. This is only the fourth section of the book&mdashhe is climbing toward realizations, merely filtering at the moment. These thoughts becomes true in the end, when Herzog is able to come to terms with uncertainty and the faith mentioned in the quote.
The quote brings in the elements of faith and religion which are important because, by the end, Moses admits to having faith and even writes a letter to God, accepting God's uncertainty as both the king of death and life. This faith is also important because it ties Moses to his Jewish background and his family, which is very important to Moses. His filial feelings run high throughout the novel, and a connection to God, in the end, makes them stronger. Moses is able to understand that having a paradoxical faith in things that are not concrete and certain is all part of life—that having faith in other people and in the unknown and in the moments he experiences (moments of pure happiness) is what makes his life worth living.