When Steve Jobs stepped down from his position as Apple CEO in 2011, he left behind some very big shoes to fill. By almost every measure, Jobs's successor--Tim Cook--has met the challenge and perhaps even exceeded it.

Yesterday, Tim Cook gave the commencement address for the Stanford University Class of 2019--as it turned out, 14 years after Steve Jobs gave the commencement address to the Stanford graduating class in 2005. In this address, Tim Cook invoked the memory of Steve Jobs, and challenged students to be builders of the future.

Said Cook,

No matter where you go, no matter what you do, I know you will be ambitious. You wouldn't be here today if you weren't. Match that ambition with humility--a humility of purpose.

That doesn't mean being tamer, being smaller, being less in what you do. It's the opposite, it's about serving something greater. The author Madeleine L'Engle wrote, "Humility is throwing oneself away in complete concentration on something or someone else."

In other words, whatever you do with your life, be a builder.

You don't have to start from scratch to build something monumental. And, conversely, the best founders--the ones whose creations last and whose reputations grow rather than shrink with passing time--they spend most of their time building, piece by piece.

Builders are comfortable in the belief that their life's work will one day be bigger than them--bigger than any one person. They're mindful that its effects will span generations. That's not an accident. In a way, it's the whole point.

Cook reminded the audience that 14 years earlier, Steve Jobs had stood on the same stage and offered the following sage advice: "Your time is limited, so don't waste it living someone else's life."

Cook offered his own corollary to his predecessor's advice: "Your mentors may leave you prepared, but they can't leave you ready." Cook explained his corollary in terms of what he personally experienced after the death of Steve Jobs:

And when he was gone, truly gone, I learned the real, visceral difference between preparation and readiness.

It was the loneliest I've ever felt in my life. By an order of magnitude. It was one of those moments where you can be surrounded by people, yet you don't really see, hear or even feel them. But I could sense their expectations.

When the dust settled, all I knew was that I was going to have to be the best version of myself that I could be.

I knew that if you got out of bed every morning and set your watch by what other people expect or demand, it'll drive you crazy.

So what was true then is true now. Don't waste your time living someone else's life. Don't try to emulate the people who came before you to the exclusion of everything else, contorting into a shape that doesn't fit.

Ultimately, we must all make our way in the world. True success comes from following our own path--our own North Star--and not the path that someone else proscribes for us. Cook left students with one last bit of advice: to leave something worthy behind. Said Cook:

There are too many people who want credit without responsibility.

Too many who show up for the ribbon cutting without building anything worth a damn.

Be different. Leave something worthy.

And always remember that you can't take it with you. You're going to have to pass it on.

Good advice for all of us, no matter what path we take in life.