Discipline does not mean suppression and control, nor is it adjustment to a pattern or ideology. It means a mind that sees 'what is' and learns from 'what was'.
Well, let's distinguish religion from spirituality. I am Catholic, so religion for me is a way of having discipline and collective worship with persons who share the same mystery.
It has been said that the great scientific disciplines are examples of giants standing on the shoulders of other giants. It has also been said that the software industry is an example of midgets standing on the toes of other midgets.
Until you have the inner discipline that brings calmness of mind, external facilities and conditions will never bring the joy and happiness you seek. On the other hand, if you possess this inner quality, calmness of mind, a degree of stability within, even if you lack the various external factors that you would normally require to be happy, it will still be possible to live a happy and joyful life.
What is the next step, the practical application? —I will answer that the absolutely vital thing is to consolidate your understanding, to become capable of enjoyment, of living in the present, and of the discipline which this involves. Without this you have nothing to give.
No doubt it is an evil to be bound by laws, but it is necessary at the immature stage to be guided by rules; in other words, as the Master used to say that the sapling must be hedged round, and so on.
The interesting thing about golf is that the presidency requires focus and discipline, and golf requires focus and discipline. It was a way to make sure that parts of my life were focused and disciplined.
Either you think, or else others have to think for you and take power from you, pervert and discipline your natural tastes, civilize and sterilize you.