Nehemiah 8:10 KJV
Then he said unto them, Go your way, eat the fat, and drink the sweet, and send portions unto them for whom nothing is prepared: for this day is holy unto our Lord: neither be ye sorry; for the joy of the Lord is your strength.
The reason why a lot of Pastors & Ministers have lost their fire in their ministry is because they let go of what inspires & motivates them.
Find out for yourself what are those things that personally motivates and inspires you. Make a list. Promise yourself that you would never neglect anything on that List.
Then the fire that burns within you would never go out. Your Passion will never burn out. Doing ministry will never grow stale.