Complete peace equally reigns between two mental waves.

The line uses a common yogic metaphor: thoughts are “waves” (vrittis) rising and falling in the mind. Sivananda’s point is that peace is not something the mind manufactures by adding more thought; it is what is naturally present in the brief interval when one thought subsides before the next arises. In meditation, practitioners learn to notice and lengthen these gaps—through attention, breath regulation, and detachment—so that the underlying stillness becomes more continuous. The quote thus reframes tranquility as the mind’s baseline when mental activity pauses, aligning with classical Yoga’s aim of quieting mental modifications to reveal inner calm.