Facebook COO and founder of the Lean In movement Sheryl Sandberg delivered an emotional commencement speech last week to the graduating class of Virginia Tech.

Sandberg is a gifted storyteller who, in the past few years, has come to appreciate the power of story to launch movements, inspire audiences, and now, to build resilience--the ability to bounce back after business failures or personal tragedies.

"We build collective resilience through shared narratives," Sandberg told the graduates of Virginia Tech. "Stories are vital. They're how we explain our past and they are how we set expectations for our future. And they help us build the common understanding that creates a community in the first place."

Sandberg began the commencement speech with her personal story of loss.

Two years and 11 days ago, I lost my husband, Dave, suddenly and unexpectedly. Sometimes I still have a hard time saying the words because I can't quite believe it actually happened. I woke up on what I thought would be a totally normal day. And my world just changed forever ... "

Since that day, with the help of psychology professor and friend Adam Grant, Sandberg has learned that resilience is a muscle that can be strengthened. And it's the power of narrative that helps communities build those muscles together, a collective resilience.

Shared narratives are critical for fighting injustice and creating social change. A few years ago, we started LeanIn.Org to help work toward gender equality--helping women and men form Lean In circles, small groups that support each other's ambitions. There are now more than 33,000 Circles in 150 countries. But it wasn't until I lost Dave that I understood why Circles are thriving--it's because they build collective resilience.

Sandberg learns to lean on the power of story.

The world may never have heard of Lean In had it not been for Sandberg's transformation as a storyteller.

It was Sandberg's inner circle--including her husband and some close friends--who helped her recognize the power of story to move people.

When Sandberg began to prepare a presentation about women in the workplace for TEDWomen 2010, she had amassed a mountain of statistics to support her message. She left her house in San Francisco and arrived in Washington, D.C., where the conference was taking place. She was troubled about leaving her 3-year-old daughter at home; she had clung to her and cried, "Mommy, don't go!" A friend of Sandberg's encouraged her to set aside some statistics and to begin telling her own personal stories. Sandberg, reluctantly at first, opened up and showed vulnerability by talking about her struggles as a working mother.

Sandberg followed her friend's advice. The presentation went viral and led to a mega-best-selling book, Lean In. But even while she was writing the book, Sandberg said, the first drafts contained far more statistics than stories. Her husband, Dave, was the one who encouraged her to bring the human side to her writing.

At another TED Conference a few years later, Sandberg explained the backstory to the book.

I wrote a first chapter; I thought it was fabulous. It was chock-full of data and figures. I had three pages on matrilineal Maasai tribes, and their sociological patterns. My husband read it, and he was like, this is like eating your Wheaties. No one--and I apologize to Wheaties--no one, no one will read this book. And I realized through the process that I had to be more honest and more open, and I had to tell my stories.

Today Sandberg shares her touching personal story very openly on stage, in television interviews, and on her Facebook posts.

As Sandberg discovered, sharing personal stories publicly isn't always easy, and sometimes we need a little encouragement to do so. But the results are magical. As humans, we are wired for story. It's in our DNA, which is why storytelling is the single best linguistic tool we have to inspire our audiences and move people to action.