Mantra is a vehicle to bring our minds, hearts and prana to the level of both primal sound and primal meaning , in which we can return to the original state of unity with all. This requires that we use mantras with an intention, focus and aspiration to reach the supreme.
Prana , [we could say], is the spirit of mantra. Mantra in turn is the expression of Prana. Whatever most engages our Prana or vital energy becomes the main subject of our speech.