My hope is Donald Trump will focus on building bridges instead of walls.

My grandmother didn't live to see us begin our lives in public service. But she probably would have thought it extraordinary that just two generations after she arrived in San Antonio, one grandson would be the mayor and the other would be on his way - the good people of San Antonio willing- to the United States Congress.

My grandmother spent her whole life working as a maid, a cook and a babysitter, barely scraping by, but still working hard to give my mother, her only child, a chance in life, so that my mother could give my brother and me an even better one.

A couple of years ago, my wife, Erica, and I were getting our daughter ready for school and an image of President [Barack] Obama was on one of the morning shows. And I said, oh, look, Carina, there's the president. You can be president one day. And she said, right away, that's for boys. And so right away I said, oh, no, you can be a doctor. You can be a lawyer. You can be anything you want. You can be president.

Opportunity today, prosperity tomorrow.

The American dream is not a sprint, or even a marathon, but a relay. Our families don't always cross the finish line in the span of one generation. But each generation passes on to the next the fruits of their labor. My grandmother never owned a house. She cleaned other people's houses so she could afford to rent her own. But she saw her daughter become the first in her family to graduate from college. And my mother fought hard for civil rights so that instead of a mop, I could hold this microphone.

I stand before you tonight as a young American, a proud American, of a generation born as the Cold War receded, shaped by the tragedy of 9/11, connected by the digital revolution and determined to re-elect the man who will make the 21st century another American century - President Barack Obama.