The teacher prepares the environment, designs the activity, functions as a guide, and offers the child stimulations; but it is the child who learns, who is motivated through the work itself (not solely by the teacher’s personality) to persist in the chosen task.
Dr. Montessori recognized that the only valid impulse to learning is the self-motivation of child.  Children move themselves toward learning. The teacher prepares the environment, designs the activity, functions as a guide, and offers the child stimulations; but it is the child who learns, who is motivated through the work itself (not solely by the teacher’s personality) to persist in the chosen task.