Discipline is there because of three reasons:
First is love. Although in love there is no need for discipline, but through love, discipline can be achieved.
Second is fear. Suppose you say to someone, ‘If you don’t observe discipline, you will fall sick,’ then that person will become disciplined out of fear of sickness.
Third is greed. Suppose you tell someone, ‘If you don’t observe discipline, you will incur a loss,’ that person will become disciplined out of greed.
So it is better to have discipline out of unconditional love; that is the best.