To be disciplined, means “to be controlled, restrained, well-organized, regular, orderly, and regimented”.

Then was Jesus led up of the Spirit into the wilderness to be tempted of the devil.  And when he had fasted forty days and forty nights, he was afterward an hungered.
Matthew 4:1,2
Jesus subjected Himself to the strict discipline of fasting for forty days and nights.  That is no mean achievement!  Anyone who has fasted without eating for even three days and nights will discover the terrible strain it puts on your self-control.
To be a great leader you must discipline yourself in prayer, fasting and reading the Bible.  There are times I stay in one room for eight hours, praying to the Lord.  I can stay alone for hours in the presence of the Holy Spirit. You cannot do this without self-discipline.
Do you want to be a great leader?  It is time to discipline yourself in every way.  To write this book, involves great self-discipline.  For hours and hours, I transmit unto the paper the words that you are reading.  It has not been an easy task!  But I know that there will be no great achievement without great discipline.

Five Things Every Leader Should Be Disciplined About

1. Be disciplined and have a daily quiet time
2. Be disciplined and spend hours in prayer.
3. Be disciplined and read your bible everyday.
4. Be disciplined and read Christian books.
5. Be disciplined and fast often.
6. Be disciplined and spend time waiting on the Lord.
7. Be disciplined and do away with useless socialising.