The anchor of CBC's The National was so touched by a speech given earlier this year by the mayor of Calgary, some themes made it into a convocation address he gave at the University of Calgary on Wednesday.

Peter Mansbridge U of C convocation address1:38

"It was something he said that inspired me to write what I have written for the convocation address," Peter Mansbridge told CBC News.

Mansbridge and Naheed Nenshi crossed paths at a convention in April.

"I was in Toronto a few weeks ago to receive an award from the Public Policy Forum for contributions to public policy in Canada. I actually thought 'this wasn't a very big deal,' it turned out to be a pretty big deal," Nenshi said.

"There was more than 1,000 people there, Peter Mansbridge was there. The prime minister was the emcee. I thought I would take that as an opportunity to give a short address about big thinking."

Nenshi says hate and divisiveness have to be confronted head on, online and in real life.

"The kind of incredibly powerful pluralistic fabric that we have built here in this community, in this country, is incredibly powerful," he said.

But that fabric and community won't maintain itself.

"We have seen these voices of intolerance and division grow louder and louder and louder, almost like those that want to tear us apart are prevailing over those that want to bring us together," Nenshi said. "We can be smug about this as Canadians and say that doesn't happen here. It happens here. Of course it happens here."

The mayor says it's time to fight back.

"We are not defined in this place by the lack of hatred, we are defined in how we respond to it. It is up to every one of us, to use our everyday hands and our everyday voices to ensure that we continue to fight for a community of opportunity for everybody. And that we fight against these voices that we find online, and in line at the Tim Hortons and everywhere else," he said.

"It is actually an existential threat to what we built here in Canada and to our success here."