"That practice, however, becomes firm of ground only when pursued and maintained in assiduous and complete observance for a long time, without interruption and with a positive and devout attitude." Swami Veda Bharati
Explanation: The reason for practice is to create a new habit of calmness, and the practice has to be strong enough to overcome the old very entrenched habit of restlessness. Forming a new habit always takes sustained effort over time. To overcome restlessness requires a very focused and devoted effort, practiced regularly (daily or in every moment), with discipline, knowledge of the goal and of the proper method, and reverence for the practice.