It makes no difference. There is no transcendent truth or power beyond man himself. Sartre doesn't believe in any God, nor does he believe that there is any preconceived design. There is no principle of authority to determine action. He says one must invent an original solution for each situation.
Morality is rooted in human choice.
Man alone gives his life its importance. Mankind must somehow transcend a life of absurdity and despair. They believed that mankind was getting better, that peace and prosperity would rein. They were convinced that we had finally figured out how to live together in harmony and to build a better world. Then came the rude awakening of two world wars and the hideous crimes against human beings perpetuated by Hitler's Third Reich.