The source of sorrow is being locked out of paradise. And sorrow is a method we use to stay within humanity.
Purity is like a ginormous alien spaceship. So big it covers the entire sky. And too alien to be remotely related to humanity. We know within it’s nonindigenous walls, if we were to be wooshed up within it, there is unspeakable delight; the complete absence of fear. Yet we are locked out. Unable to Scotty ourselves up. We have to relinquish ourselves before we are wooshed up. And once relinquished we are no longer human and no longer ourselves. That is the source of sadness.