Pope Francis has challenged young people to commit to practicing the corporal works of mercy in order to recognize the face of Jesus in each other.

"As you know, the works of mercy are simple gestures, which belong to the life of every day, allowing you to recognize the face of Jesus in many persons. Even young people!" the Pope said in a video message to a youth rally at Rome's Olympic Stadium.

"Even young people like you, who hunger, who thirst; who are refugees, or foreigners, or sick, and seeking our help, our friendship."

Saturday's rally was part of a three-day Jubilee of Mercy event geared toward young people. The event kicked off Saturday with a pilgrimage to the Holy Door at St. Peter's Basilica. Then priests – and even the Pope – heard confessions in St. Peter's Square.

In his video message Saturday, the Holy Father said mercy necessitates forgiveness, which he admitted is not easy.

"It can happen that, at times, in the family, at school, in the parish, at the gym, or in places of amusement, someone can do us wrong and we feel offended; or, in a moment of irritability," we can be the ones who offend others, he reflected.

But, the Pope warned, revenge is "a worm which eats our soul and does not allow us to be happy."

"Let us not remain with resentment or the desire for revenge!" he urged the young people. "Let us forgive! Let us forgive and forget the wrong done…in order that we may understand the teaching of Jesus and be his disciples, and be witnesses of mercy."

The Pope expressed his regret at not being able to join the young people at the Olympic Stadium. Francis will rejoin the young pilgrims Sunday for Mass at St. Peter's Basilica.

"You have gathered for a moment of celebration and joy," he said. "This morning you transformed St. Peter's Square into a great confessional, and then you went through the Holy Door."

"Do not forget that the Door points to an encounter with Christ, who introduces us to the love of the Father, and who asks us to become merciful, as he is merciful."

The Pope also encouraged young people to foster a personal relationship with Jesus. He warned Christians risk closing in on themselves when they are not close to Christ.

He compared a healthy relationship with Christ to a strong phone signal.

"Remember…when Jesus is not in our life, there is no signal!"