Sheryl Sandberg’s commencement speech to the graduating class of Berkeley is powerful. In her speech, she describes the lessons learnt from the death of her husband, stating that: “It is the hard days—the times that challenge you to your very core—that will determine who you are. You will be defined not just by what you achieve, but by how you survive.”

Life is filled with peaks and valleys: a moment of failure here, a period of success there, followed by a time of stagnation. But, it is in those moments of failure that professional longevity can be found. Studies have shown that the greatest predictor of success is not grades, not money, not looks, but resilience. So it is in Sandberg’s call to building resilience within ourselves that makes her commencement speech so perfect.

Everyone who has made it through Cal has already experienced some disappointment. You wanted an A but you got a B…

She was the love of your life… but then she swiped left.

Game of Thrones the show has diverged way too much from the books—and you bothered to read all 4,352 pages.

You will almost certainly face more and deeper adversity. There’s loss of opportunity: the job that doesn’t work out, the illness or accident that changes everything in an instant. There’s loss of dignity: the sharp sting of prejudice when it happens. There’s loss of love: the broken relationships that can’t be fixed. And sometimes there’s loss of life itself…

And when the challenges come, I hope you remember that anchored deep within you is the ability to learn and grow. You are not born with a fixed amount of resilience. Like a muscle, you can build it up, draw on it when you need it. In that process you will figure out who you really are—and you just might become the very best version of yourself.