be living proof of (something)

To serve as an example for why a particular statement or concept is true. As a former slacker, I know that you can turn your life around if you work hard enough—I'm living proof of that. Those guys made every wrong move when they started their business, and now they have one of the most successful companies in the world. They're living proof of the potential to overcome even the most expensive of mistakes. My parents have been married over 50 years. They're living proof of the existence of true love.