"Just do what must be done. This may not be happiness, but it is greatness.

Doing what needs to be done may not make you happy, but it will make you great.
Doing what needs to be done may not make you happy, but it will make you great.
Doing what needs to be done may not make you happy, but it will make you great.
Doing what needs to be done may not make you happy, but it will make you great.