God with a body, God of the future

While he was a prisoner of war in 1940, Jean-Paul Sartre wrote a nativity play. He is primarily remembered as a philosopher, but he also wrote novels, films, songs, and plays so his wartime playwriting isn’t too surprising in that regard. However, as a famously public atheist, a play about the coming of Jesus seems like a strange topic for Sartre. Why did he write this? The play is…