"We cannot turn a blind eye to images like the ones we've seen out of Syria," Obama said in his weekly address.
"We can't ignore chemical weapons attacks like this one, even if they happen halfway around the world. And that's why I call on Members of Congress, from both parties, to come together and stand up for the kind of world we want to live in, the kind of world we want to leave our children and future generations," he said.
He contended that the action in Syria "would not be another Iraq or Afghanistan".
The Obama administration has accused President Bashar al-Assad's forces of killing 1,429 people in a poison-gas attack in the suburbs of Damascus on August 21, a charge denied by the Syrian government.
More From This Section
Both the House of Representatives and the Senate are expected to debate and vote on the authorisation resolution next week.
Obama's plans for a military strike against the Assad regime suffered a setback last week when his ally Prime Minister David Cameron's resolution seeking authorisation for action suffered a shock defeat in the British Parliament.
Many world leaders at the just-concluded G20 summit also did not agree with Obama's plans for a strike.
Amid deep global divisions over US plans for strikes, US Secretary of State John Kerry travelled to Europe to seek support for military action.
Kerry held informal talks with the EU's 28 foreign ministers in Lithuania, which currently holds the EU's rotating chair, with the bloc itself sharply split on the issue.