All man made purposes will fail us.
For those who do not believe in God, I am curious on why? There is historical legitimacy to the Bible so I am assuming those who reject God also deny the historical account of the Bible? We
Can't reject parts of history we want to believe and only choose to believe parts of history we want. Jesus was an actual man who walked the Earth. The most important question life is who we say Jesus is. See Matthew 16:16.
For purpose, see Romans 8:28. "And we know that for those who love God all things work together for good, for those who are called according to his purpose."