People think that strength comes from selfish motivation. But reality is that strength and devotion towards any work comes from selflessness.
It is selflessness that makes you an indestructible force. It is selflessness that makes you do your duties with complete devotion.
It is a psychological game. If you increase base of your identity bigger, you become mentally stronger.
For most people, their identity is just their body. But if they extend their identity to their family, they become little stronger. If they identify themselves with their society, they become more stronger.
And when they identify themselves with their country, they become more stronger. And when they identify themselves with this universe, they become strongest.
For instance, a lethargic person may also become active when it comes to feed his family.
Similarly, someone who is working for nation’s military work will have very strong devotion. He can tolerate all wounds and pain he get while fighting for his country.
In same way, A person who see his duty or his work as a service to the ultimate reality will work with a very strong devotion.
I request all the readers to share ways they think that can be applied here. Just a mental activity for you.