Larry Parsley convincingly writes on the need to recognize our limitations:

Henry Worsley, a former British army commando and then Arctic explorer, was obsessed with his leadership hero, the Arctic explorer Earnest Shackleton. Worsley (who once spent the night sleeping near his hero's grave) adopted Shackleton's creed: "By endurance we conquer."

But despite his fame and heroism, Shackleton was in many ways a broken man. He emerged physically broken after Captain Robert Scott's 1902 retreat from his polar expedition. In 1906, Shackleton led his own valiant yet unsuccessful journey toward the South Pole, eventually ordering a retreat to save the lives of his men.

Worsley's obsession with endurance pushed him beyond his previous milestones. He had internalized a line from a James Elroy Flecker poem: "always a little further … a little further." And so, at the age of 55, Worsley set off for what he hoped would be an 80-day solo journey. He endured temps of minus-40 degrees Fahrenheit, was often disoriented, windblown, dodging deadly crevasses, all the while pulling a sled nearly double his own weight. After covering over 900 miles in a little over two months, Worsley's body became battered by various illnesses, dehydration, and sheer exhaustion. Just 30 miles from his goal, a defeated Worsley radioed for an airlift. Sadly, his body was by then too far gone, and he passed away from organ failure before his wife Joanna could see him.

It is easy to lionize Worsley, who seemed to have near superhuman discipline, but a recent article about Worsley in the New Yorker magazine observes:

In his diary, he [Worsley] had written, "Never, ever give in." It echoed a lesson from one of the Shackleton self-help books, which Worsley had once posted on his Web site: "Never give up—there's always another move."

But maybe that was wrong. Hadn't Shackleton survived because he had realized that, at a certain point, he had no more moves and turned back? Unlike Scott and others who went to a polar grave, Shackleton reckoned with his own limitations and those of his men. He understood that not everything, least of all the Antarctic, can be conquered. And that within defeat there can still be triumph—the triumph of survival itself.

At some point in our lives the real key is not "always a little further." At some point we need to hear "Come to me all who labor and are heavy laden." Real power lies in surrender, admitting our weakness and limitations and trusting the power of the Holy Spirit.