Only oneself must decide. This man chose that all his experiences meant that he was called by God to serve God directly in his life by choosing the means of becoming a priest. He created, or perhaps better, he co-created with God his purpose and his means to his purpose. Such a choice can be very difficult precisely because we cannot know with certitude what we should do with our lives. This lack of certainty over our purposes can give rise to the deep experiences of anxiety and despair, revealing the suffering involved in the inescapable demand that each person choose the meaning of life.
Freedom is the center of human existence.
Those who refuse to recognize the dominance of freedom over all aspects of personality are for Sartre living in self-deception, hiding from what they are choosing to do to themselves. Sartre denies that there is an essence in human nature which limits freedom.