"She was very worried that the language was coarsening and people were driven to take more extreme positions," he told the BBC.
Cox was a rising star of the Labour party and a vocal advocate of Britain remaining in the European Union. She championed for the rights of immigrants and was particularly vocal about Syrian child refugees.
Last week, the 41-year-old politician was fatally shot and stabbed in Birstall in northern England.
Cox said he believes his late wife was killed because of what she believed in.
"She had strong political views and I believe she was killed because of those views," Cox said. "She died because of them. She would want to stand up for those in death as she did in life."
International outpouring of love
Tommy Mair, the man accused of killing Cox had said in a brief court appearance on Saturday
, "Death to traitors, freedom for Britain."
The shocking killing of Cox last week has focused international attention on the country's pivotal referendum on whether to leave the European Union. United Kingdom voters head to the polls Thursday.
Cox said he was grateful for the outpouring of love from around the world and that he had even heard that a school in a refugee camp had been named after his late wife.
Cox said he would not run for election for his wife's Parliament seat, saying that Jo would've wanted a woman to take the spot. He said he would focus on taking care of their two children and making sure that something good could come from the tragedy.
"She'd want this to try bring people together, bring more compassion for each other, to dial down the rhetoric, hatred and bring communities together," Cox said.