"When one does not confess Christ," he said, "one confesses the worldliness of the devil."
The Pope spoke at Mass March 14 in the Sistine Chapel, site of the conclave that had elected him the previous day. Pope Francis concelebrated the Mass with the 114 other cardinal electors who had taken part in the conclave.
Following the cardinal electors in a procession, all of them wearing gold vestments to signify joy, the Pope entered the chapel as a choir sang in Latin a verse from Mt 16:18, which begins "tu es petrus" (you are Peter).
In one of the first signs of change from the previous pontificate, Pope Francis celebrated Mass at a temporary altar that allowed him to face the rest of the congregation. In recent years, Pope Benedict XVI had celebrated Mass in the Sistine Chapel at an altar fixed to the wall under Michelangelo's fresco of the Last Judgment.
The new Pope also delivered his homily standing at a lectern, not seated, as his predecessor usually did.
Preaching for seven minutes in Italian without a written text or notes, Pope Francis spoke about three important kinds of movement that he said appeared in the Scripture readings at the Mass: walking, building and confessing.
"Our life is a path," he said. "When we stop, the thing doesn't go." He said Catholics must "walk always, in the presence of the Lord, in the light of the Lord, seeking to live with that blamelessness that God asks of Abraham in his promise.
"Build with living stones, anointed by the Holy Spirit," the Pope said. "Confess Jesus. If we don't do that, we will be a pitiful NGO (non-governmental organization)."
He also compared building without faith to sand castles children construct on the beach, which are washed away by the next tide.
"To walk, build and confess without the cross means that we are not true disciples of the Lord," he said.
"We must confess the one cross, and in that way we will be a true Church.
"I would like that all of us, following these days of grace, have the courage — the very courage — to walk in the presence of the Lord, with the cross of the Lord," the Pope said in conclusion; "to build the Church in the blood of the Lord, which is spilled on the cross; and to confess the only glory, Christ crucified. And in that way the Church will move ahead."
Pope Francis - A New Era
