You say the work is important. But why? What’s so important about it? Why are you doing it?
Knowing the answer will keep you going when you are at your lowest ebb of motivation. When you’re ready to give up, to give in, knowing why will help you push passed and make the extra effort. But only if your why is strong.
Why can rally others to your cause. Why can bring followers, others to help do the work or spread the work. But only if your why is strong.
A weak why will sap your strength, your energy. Find a strong why, or if the work does not lend itself to a strong why, find work that does.