At a six-day conference in Rome with 300 youth in attendance he said: "Be brave in these days. Say what you have to say. If you err, someone will correct you. I have faith that in these days God will speak ... through you."
He also dared youth to have new opinions and thoughts, "even if it means taking risks."
Pope Francis added: "A man or woman who does not risk does not mature. An institution that chooses not to risk remains a child, it does not grow up.
"That's why we need you young people, living stones of a church with a young face.
"You provoke us to break free of the logic of 'it has always been done this way', which is a sweet poison that tranquilizes the soul."
Pope Francis made the comments at the meeting on Monday in preparation for a Synod of Bishops meeting, which convenes in October.
The focus of the meeting will be on issues facing youth today.
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