“True rest for muscles, intended by nature for action, is in orderly action; just as true rest for the lungs is the normal rhythm of respiration taken in pure air. To take action away from the muscles is to force them away from their natural motor impulse, and hence, besides tiring them, means forcing them into a state of degeneration; just as the lungs forced into immobility, would die instantly and the whole organism with them.” – Maria Montessori

Likewise, true rest for human beings is when are strengths and abilities are needed and necessary to an outcome larger than ourselves. – Anthony Decker 

Montessori, M. (2011-07-19). The Montessori Method (Kindle Locations 6690-6693). Kindle Edition.