Saying his glasses "aren't working," Pope Francis put aside his prepared text and told representatives of Portuguese charities to make their love "concrete" and leave a mark on the world with their lives.

"There are many things I want to tell you now," Pope Francis said with a smile at a parish in the Serafina neighborhood on the outskirts of Lisbon Aug. 4, but "I can't read well" and don't want to "strain the vision and read poorly." So, he said, "I just want to say something that is not written but is in the spirit of this (text): the concrete."

"There is no abstract love, it doesn't exist," the pope said. "Concrete love is that which gets its hands dirty."

Pope Francis urged the charity workers to ask themselves, "The love that I feel, is it concrete or abstract?" and posed another question while vigorously rubbing his hand against his cassock: "When I shake the hand of someone in need, a sick person, a marginalized person, do I do this right after, so they don't infect me? Am I disgusted by poverty?"

Before speaking, the pope listened to representatives from Portuguese charities, including an association that cares for the families of children with cancer and another that works with at-risk youth, talk about the impact they have had on the people they serve.

"You can't talk about World Youth Day without having this reality in mind," Pope Francis told the charity workers on the third day of his trip to Portugal to participate in the international gathering of young people.

All who dedicate themselves to charity, he said, stay young, because by "getting your hands dirty by touching the reality and misfortune of others, you are creating an inspiration, you are generating life."

"Don't be discouraged," the pope told them. "And if you get discouraged, drink a glass of water and keep moving forward," he said to laughs from the crowd.

Walking over to greet the choir of children assembled alongside him on stage after his speech, the pope was met with timid waves from children saying "Olá," "hello" in Portuguese. Pope Francis taught them how to say hello in Italian and raised his hand to his ear, prompting them to loudly repeat it back to him, "Ciao!"

Using a wheelchair, the pope then went next door to the parish church, where he greeted children, young people and several elderly persons who smiled at him from their own wheelchairs.

Returning to the Vatican nunciature where he is staying in Lisbon, Pope Francis met with a delegation from the KAICIID International Dialogue Centre, accompanied by Cardinal Miguel Ángel Ayuso Guixot, prefect of the Dicastery for Interreligious Dialogue.

The center, which has its headquarters in Lisbon, was formed out of the need for greater interfaith dialogue identified in a meeting between Pope Benedict XVI and King Abdullah of Saudi Arabia in 2007. The Vatican said Pope Francis discussed "the value of fraternity and dialogue" with the delegation and noted the "danger of proselytism."

He immediately put those principles into action, meeting also with Prince Rahim Aga Khan, a prominent figure in the Isma'ili Muslim community -- a branch of Shia Islam-- and a group representing different faiths and Christian denominations that work in ecumenical and interreligious initiatives in Portugal.