Discipline is only a by-product.  If you start with it, it will only get you a short distance.  Like a battery, in the short run, it will work.  A battery is useful but is short lived.  Unless this battery is re-charged, it is useless.

Enthusiasm works better than discipline.  Enthusiasm is more of an emotional state.  It is a spiritual commitment, a loving surrender to a Higher Calling.  And in that sense, it can never run dry.  It is an ongoing energy supply tapped into the flow of life itself.

Think of flowing river. We can build dams on the river to control the water-flow.  We can re-direct the flow of the river by digging artificial canals or creating artificial lakes, ... etc.  But if the river is cut at the source; if no rain is falling down, the dams don't serve much.

Same with discipline.  We can use it to direct our enthusiasm.  But when there is no enthusiasm; when there is no passion: what can discipline do for us?

salam
Ahmad