In a deeply emotional video released Saturday morning, Wheeler reminisces about how Ben sang with perfect pitch, was learning to play piano and wanted to be an architect or, like his big brother dreamed of, a paleontologist. Then, her voice cracking and eyes welling with tears as she sits beside her husband, Wheeler pleads with the nation to call their senators and urge them to pass the gun-control legislation they began considering this week.

“We have to convince the Senate to come together and pass commonsense gun responsibility reforms that will make our communities safer and prevent more tragedies like the one we never thought would happen to us,” Wheeler says in the four-minute 20-second video produced by the White House.

Wheeler’s remarks are a heart-wrenching capstone to a week of intense lobbying in Washington by parents of children slaughtered at Sandy Hook Elementary School. After Obama issued a forceful call for swift action during a campaign-style rally in Connecticut on Monday, he brought about a dozen Sandy Hook parents with him to Washington aboard Air Force One. The parents spent the week meeting personally with senators to lobby them to support stricter gun laws, including the expansion of background checks for all gun buyers.

“When I packed for Washington on Monday, it looked like the Senate might not act at all,” Wheeler says in the video. “Then, after the president spoke in Hartford, and a dozen of us met with senators to share our stories, more than two-thirds of the Senate voted to move forward. But that’s only the start. They haven’t yet passed any bills that will help keep guns out of the hands of dangerous people. And a lot of people are fighting to make sure they never do.”

Obama asked Wheeler to deliver the weekly address, which is aired nationally on television and radio and is almost always given by the president. She becomes the only person other than Obama or Vice President Biden to deliver the address during this administration, a White House official said. Wheeler wrote the remarks with her husband, the official added, and together they taped the video on Friday morning in the library at the White House.

Wheeler says in her remarks that Ben’s killing has given her the courage to advocate for gun policy changes in Washington.

“I’ve heard people say that the tidal wave of anguish our country felt on 12/14 has receded,” she says. “But not for us. To us, it feels as if it happened just yesterday. And in the four months since we lost our loved ones, thousands of other Americans have died at the end of a gun. Thousands of other families across the United States are also drowning in our grief. Please help us do something before our tragedy becomes your tragedy.”