Elton Trueblood said this quote

“ We have not advanced very far in our spiritual lives if we have not encountered the basic paradox of freedom, to the effect that we are most free when we are bound. But not just any way of being bound will suffice; what matters is the character of our binding. The one who would like to be an athlete, but who is unwilling to discipline his body by regular exercise and by abstinence, is not free to excel on the field or the track. His failure to train rigorously and to live abstemiously denies him the freedom to go over the bar at the desired height, or to run with the desired speed and endurance. With one concerted voice the giants of the devotional life apply the same principle to the whole of life with the dictum: Discipline is the price of freedom. ”