Charlie Kirk’s widow Erika has delivered an emotional 20-minute eulogy forgiving her husband’s killer and vowing to continue his work.

Erika Kirk was one of the key speakers when tens of thousands of people packed into State Farm Stadium in Glendale, Arizona, on Sunday (local time) to mourn the slain right-wing influencer.

“That man, that young man, I forgive him. I forgive him because it was what Christ did and is what Charlie would do,” she said, adding that the answer to hate was love, as taught in the Gospel.

Christian rock music blared through loudspeakers and pictures of Kirk were set on easels throughout the walkways of State Farm Stadium. The arena, which has a capacity of 63,000, appeared completely full.

Crowds of people, many wearing MAGA merchandise, arrived before dawn to secure seats inside the stadium, where they encountered metal detectors amid tight security.

The memorial, organised by Kirk’s conservative youth advocacy organisation Turning Point USA, had the feel of a religious revival mixed with a “Make America Great Again” political rally.

During her eulogy, Kirk reflected on her relationship with her husband and her emotions on September 10, when he was fatally shot on a university campus in Utah.

Donald Trump embraces Erika Kirk at the memorial for her husband Charlie. Photo: AAP

The alleged perpetrator, 22-year-old Tyler Robinson, was arrested a short time later and charged with murder. He faces the death penalty.

She recalled seeing her 31-year-old husband’s lifeless body in hospital and feeling shock, horror and “a level of heartache that I didn’t even know existed”. But she said she “could see the man that I love,” with the “one, single grey hair on the side of his head” and a faint smile on his face.

“That told me something important,” she said. “It revealed to me a great mercy from God in this tragedy. When I saw that, it told me, Charlie didn’t suffer.”

Kirk also pledged to pick up where her husband left off.

“The world needs Turning Point USA,” she said. “It needs a group that will point young people away from the path of misery and sin.”

US President Donald Trump was the final speaker at Sunday’s service, arriving to cheers from the packed crowd. He said Kirk was a “martyr for American freedom” and had been killed by a “radicalised, cold-blooded monster for speaking the truth”.

Trump said Kirk was targeted because he stood “for freedom and justice, for God, country, for reason and common sense”, adding that the attack had made Kirk “immortal.”

“He was assassinated because he lived bravely, he lived boldly and he argued brilliantly,” he said.

“He’s a martyr now for America’s freedom. I know I speak for everyone here today when I say that none of us will ever forget Charlie. And neither now will history.”

Trump said that, unlike Erika Kirk, he did not wish his opponents well.

“I hate my opponents. And I don’t want the best for them,” he said.

“I’m sorry. I’m sorry Erika.”

At the end of his speech, Trump embraced Kirk, who rested her head against his chest several times as they held hands.

Earlier, powerful White House adviser Stephen Miller had vowed to use Kirk’s death as a galvanising force to finish the work he began.

“We will carry Charlie and Erika in our heart every single day, and fight that much harder because of what you did to us,” Miller said in a fiery speech.

“You have no idea the dragon you have awakened. You have no idea how determined we will be to save this civilisation, to save the West, to save the republic.”

The memorial service also included Vice President JD Vance, Secretary of State Marco Rubio and Secretary of Defence Pete Hegseth and young conservatives shaped by Kirk’s political influence.

Kirk’s death has raised fears about the growing frequency of US political violence across the ideological spectrum, while also deepening partisan divides.

During her remarks, Tulsi Gabbard, the US director of national intelligence, tied Kirk’s killing to what she described as a historical pattern in which “political fanatics” eventually turn to violence to defend their ideals.

“They kill and terrorise their opponents, hoping to silence them,” she said.

“But in this evil that we have experienced – that Charlie faced – their flawed ideology is exposed, because by trying to silence Charlie, his voice is now louder than ever.”

-with AAP