Security is being stepped up in the wake of the France church attack where an 86-year-old priest's throat was cut by two hostage-takers.
Archbishop Georges Pontier, president of the French bishops conference, said in Krakow that the attack "shocked us, it touched us, and revolted us."
He also called on Christians not to be discouraged by such inhumane acts.
After a string of attacks in Europe, Polish officials are trying to give reassurances that the nation's security forces are prepared for the massive event, which the pope will attend from Wednesday to Sunday.
Speaking to Premier from the event, Fr Kevin Hennessey said everyone was being "very cautious".
He said: "We're being very well looked after by the Polish authorities. We feel surrounded with care and protection. That's our observation of the situation just now. So, we feel safe."
The celebratory atmosphere of the event will return despite events in France, he said.
"Obviously, life is the way life is and we're all aware of the struggle of life especially at the moment with so much sadness and the awful violence Pope Francis mentioned.
"But I thought archbishop Domonique spoke very well, he said we want to make a civilisation of love. Our young people are the way forward; we don't want them to react to violence with violence. The only weapon we have is prayer and the brotherhood and sisterhood of humanity. That's what we look to. We want to be a people of hope.
"There are tens of thousands here today who are happy and joyful. That's what will keep us going. We're a people of hope.
"We're a Catholic community who want to stand together with other Christians and be a people of hope. We try to be a people of thanksgiving that we have so much good in our lives and we want to share that with others."