Great quote, challenging sentiment:
Non-discipleship costs abiding peace, a life penetrated throughout by love, faith that sees everything in the light of God’s overriding governance for good, hopefulness that stands firm in the most discouraging of circumstances, power to do what is right and withstand the forces of evil. In short, it costs exactly that abundance of life Jesus said he came to bring.
(Dallas Willard, The Spirit of the Disciplines [via Richard Foster’s Devotional Classics])
We can’t afford not to be disciples if we’re committed to following Jesus. That becomes mere religion…