One view of yoga and meditation is that it is the journey of the prana, the life force, via the vehicle of the breath to know itself and its source.
And the prana taking the form of the inhale and the exhale is itself the vehicle.
From this point of view, yoga and meditation are the journey of life back to know itself and its source–and the resulting joy and bliss in this discovery of its own magnificence.
The Every Day Yogi 