Obama spoke at the University of Hartford in Connecticut, the state where four months ago a disturbed young gunman shot and killed his mother before gunning down 20 children and six adults at a Newtown elementary school and taking his own life.
"Newtown, we want you to know that we're here with you. We will not walk away from the promises we've made. We are as determined as ever to do what must be done," Obama said in remarks prepared for delivery to the university audience.
"As soon as this week, Congress will begin debating common sense proposals to reduce gun violence. But Congress is only going to act on them if they hear from you -- the American people.
"Some back in Washington are already floating the idea that they might use political stunts to prevent votes on any of these reforms. Think about that. They're not just saying they'll vote 'no' on ideas that almost all Americans support. They're saying they won't allow any votes on them at all. They're saying your opinion doesn't matter. And that's not right.
"I've also heard some in the press suggest that what happens to gun violence legislation in Congress this week will be a political victory or defeat for me. You know what? This isn't about me. And it shouldn't be about politics. This is about doing the right thing for families like yours that have been torn apart by gun violence, and families going forward."
Obama said there are "powerful interests that are very good at changing the subject, at amplifying conflict and extremes over common ground, at drowning out rational debate by ginning up irrational fear."
"That's what too often stands in the way of progress," he said. "But if our history teaches us anything, it's that it's up to all of us -- the people -- to stand up to those who say we can't, and stand up for the change we need."
The president called on people to act.
"Now is the time to get engaged, to get involved, to push back on fear, frustration, and misinformation," he said. "Now is the time to make your voice heard from every state house to the corridors of Congress."
White House press secretary Jay Carney told reporters Obama would be meeting with parents of the Newtown victims and first responders, and that they would travel back to Washington with the president on Air Force One.
"These are family members who are planning to be in Washington to speak with Congress about the importance of taking action to reduce gun violence," Carney said. "And in order to make sure they were able to attend the event in Connecticut and still be in Washington when they needed to be, we invited those family members to fly back with the president."