"If an educational act is to be efficacious, it will be only that one which tends to help toward the complete unfolding of life. To be thus helpful it is necessary rigorously to avoid the arrest of spontaneous movements and the imposition of arbitrary tasks"

Maria Montessori is mentioning that for any academic action to be genuinely reliable, it needs to promote the complete and natural development of the person. In order to do so, it is necessary to avoid preventing the natural and spontaneous propensities of the person, and to not enforce pointless jobs that do not serve this end.