People who love to sing tend to force their voices. This is not bad, but such force cannot really engender spiritual emotions

"People who love to sing tend to force their voices. This is not bad, but such force cannot really engender spiritual emotions. They would do better to emphasize feeling, for feelings have nuances and therefore a subtler life, and the voice thus becomes more expressive. If they also add light to their interpretation, in other words a thought, the song fulfils its true mission. Singing loudly can produce impressive results, but it fails to touch the subtlest regions of the soul and spirit. Force must be present only as a raw material on which feeling works to render it expressive and thought works to give it purpose."