Ukrainian President Volodymyr Zelensky delivered a speech to the U.S. Congress on Wednesday amid the continuing Russian invasion of his country and the ongoing fighting.

It was Zelensky's first trip outside of Ukraine since the war began on February 24 in what Russian President Vladimir Putin described as a "special military operation."

Zelensky mentioned Putin by name only briefly during his speech but he implied that Russians needed a change in government and took the opportunity to thank the U.S. for the support that the country has provided thus far.

Here are five key takeaways from Zelensky's speech.

President of Ukraine Volodymyr Zelensky addresses a joint meeting of Congress in the House Chamber of the U.S. Capitol on December 21, 2022 in Washington, DC. Zelensky stressed the importance of U.S. aid to Ukraine.Chip Somodevilla/Getty Images

1. Ukraine's Resistance Is an American Victory

Zelensky emphasized the role that aid from the U.S. and its European allies has played in Ukraine's fight against the Russians. U.S. aid to Ukraine will top $100 billion if the spending bill passes.

"We defeated Russia in the battle for minds of the world. We have no fear, nor should anyone in the world have it. Ukrainians gained this victory, and it gives us courage which inspires the entire world," Zelensky said.

"Americans gained this victory, and that's why you have succeeded in uniting the global community to protect freedom and international law. Europeans gained this victory, and that's why Europe is now stronger and more independent than ever," he said.

2. Freedom for Russia

Zelensky also touched upon the present Russian government, led by Putin, and appeared to suggest a change in government will be needed in Moscow for the benefit of the Russian people.

"I know one more, I think very important, thing: The Russians will stand a chance to be free only when they defeat the Kremlin in their minds. Yet, the battle continues, and we have to defeat the Kremlin on the battlefield, yes," the Ukrainian president said.

3. The Battle Can't Be 'Postponed'

Throughout the conflict, some have suggested that the matter can be resolved through negotiation or even concessions to Russia, but Zelensky suggested in his speech that now is not the time for talk.

"The battle is not only for life, freedom and security of Ukrainians or any other nation which Russia attempts to conquer. This struggle will define in what world our children and grandchildren will live, and then their children and grandchildren," he said.

"It will define whether it will be a democracy of Ukrainians and for Americans—for all. This battle cannot be frozen or postponed. It cannot be ignored, hoping that the ocean or something else will provide a protection," Zelensky said.

4. Fighting Russia Is Like Resisting Hitler in 1944

Zelensky discussed the fierce fighting that's continuing in the city of Bakhmut in Ukraine's Donbas region. The city is a key Russian target and Zelensky paid a surprise visit this week.

The Ukrainian president compared fighting the Russian invasion to the Battle of the Bulge in 1944—a famous, last ditch effort by Hitler's forces.

"The Russians' tactic is primitive. They burn down and destroy everything they see. They sent thugs to the front lines," Zelensky said. "They sent convicts to the war. They threw everything against us, similar to the other tyranny, which is in the Battle of the Bulge. Threw everything it had against the free world, just like the brave American soldiers which held their lines and fought back Hitler's forces during the Christmas of 1944."

"Brave Ukrainian soldiers are doing the same to Putin's forces this Christmas," he said.

5. Aid to Ukraine Is 'Not Charity'

Zelensky made repeated references to the aid that the U.S. and its allies have provided, including the Patriot missile system that's part of a $1.85 billion military package unveiled by Secretary of State Antony Blinken on Wednesday.

The Ukrainian president stressed that his country's forces were well able to use the equipment they've been provided and that the aid is not mere charity.

"Ukraine never asked the American soldiers to fight on our land instead of us. I assure you that Ukrainian soldiers can perfectly operate American tanks and planes themselves," Zelensky said.

"Financial assistance is also critically important, and I would like to thank you, thank you very much, thank you for both financial packages you have already provided us with and the ones you may be willing to decide on. Your money is not charity. It's an investment in the global security and democracy that we handle in the most responsible way," he said.

Zelensky concluded his speech by giving Congress a Ukrainian flag that he had received during his visit to Bakhmut and he finished by saying: "Merry Christmas and a happy, victorious New Year. Slava Ukraini [Glory to Ukraine]."