It was a Saturday morning. Pope Francis just landed at the Philadelphia airport, and immediately boarded the modest car that will bring him to his next destination.

The Pope's convoy, however, momentarily and unexpectedly halted. The leader of the Roman Catholic Church got out of the car and walked towards 10-year-old Michael Keating, who has cerebral palsy, who was accompanied by his parents to witness the Pope's arrival at the airport, the Washington Post reported.

Pope Francis smiled, put his hand on Michael's head and kissed the severely disabled boy, as his sobbing mother, Kristin, looked on.

Kristin recalled how she could not understand what Pope told her child, words which were not in English. She nevertheless said that she felt and understood the emotion behind the Pope's word: love.

"His hands were so soft. When he kissed my son, it was wonderful. I know it's life-changing for our family," Kristin said.

Chuck Keating, the boy's father, meanwhile said his family's encounter with the Pope all the more strengthened his faith in God.

"My faith has always been strong. Michael has always been a blessing. Michael's the one who taught me the value of a hug and a kiss. He is a gift from God," the father said.

He also said that he "had to turn away" as the Pope blessed his child, saying that it was such an "overwhelming" experience.

Katie, Michael's 13-year-old sister, was meanwhile overjoyed and was reduced to tears during her brief encounter with the Pope.

"I can't even explain, I was just so happy," Katie shared. Michael's grandmother and his twin brother, Christopher, were also there to witness the once-in-a-lifetime moment with the Pope.

The Pope's encounters with children have been some of the highlights of the his historic six-day apostolic visit to the United States. Earlier, he embraced a five-year-old daughter of two undocumented immigrants outside of the White House—photos of which went viral on the Internet.