An inspiring example from the journals of Sir Ernest Henry Shackleton, leader of the failed Imperial Trans-Antarctic expedition of 1914-1916:
"The thought of those fellows on Elephant Island kept us going all the time. It might have been different if we'd had only ourselves to think about. You can get so tired in the snow, particularly if you're hungry, that sleep seems the best thing life has to give. But if you're a leader, a fellow that other fellows look to, you've got to keep going. That was the thought which sailed us through the hurricane and tugged us up and down those mountains [of South Georgia Island]… and when we got to the whaling station, it was the thought of those comrades which made us so mad with joy that the reaction beats all effort to describe it. We didn't so much feel that we were safe as that they were saved."
Here's a link to the James Caird Society, named after the small lifeboat that carried Shackleton and five others 800 miles across Drakes Passage to South Georgia Island in the depths of an Antarctic winter.