President Barack Obama used Saturday night’s House vote in favor of health care reform to raise money for the grass-roots group Organizing for America, telling its 13 million members that the victory heralds a tough fight in the Senate and that OFA needs their financial support.

“The final Senate bill hasn’t even been released yet, but the insurance companies are already pressing hard for a filibuster to bury it,— Obama said in an e-mail message sent early Sunday morning.

“OFA has built a massive neighborhood-by-neighborhood operation to bring people’s voices to Congress, and tonight we saw the result,— the president wrote. “But the coming days will put our efforts to the ultimate test. Winning will require each of us to give everything we can, starting right now. Can you donate $25 or whatever you can afford so we can finish this fight?—

Obama congratulated the members of the group for their work on behalf of the House bill. “You stood up. You spoke up. And you were heard,— he said. OFA is backed by the Democratic National Committee and formed from the Obama presidential campaign’s vast e-mail list

Obama will make a statement early Sunday afternoon in the Rose Garden about the House vote to pass health care reform. The president will speak soon after his scheduled return from Camp David, where he spent Saturday night while the House voted on the bill.

In addition to calling House Democratic leaders after the vote to congratulate them, Obama also called AARP CEO Barry Rand, American Nurses Association President Rebecca Patton and Rebecca Patchin, chairwoman of the Board of Trustees of the American Medical Association, to thank them for their support.