Why is pranayama about expanding bio-energy and then returning to the original source?

According to Osho, pranayama mirrors life’s essential polarity: the out-breath expands life-energy into the world, and pratyahar—the in-breath—returns it to its origin, inner emptiness. Life is a river flowing between these opposites; creation and dissolution, birth and death. Practicing this rhythmic expansion-and-return harmonizes consciousness with the divine pattern—empty within, whole without—transcending logic and making one godly.