It (Tao) is eternally without desire. So, it can be called small. All things return to it, although it does not make itself their ruler. So, it can be called great.
When you accurately perceive the fluidity of things, you can also begin to perceive the constancy behind them: the creative, transformative, boundless, immutable Tao.
When the Way is lost there is virtue. When virtue is lost there is benevolence. When benevolence is lost there is righteousness. When righteousness is lost there are rituals.