Cardinal Marc Ouellet, prefect of the Vatican's Congregation for Bishops, said the Catholics of America should be "on the front lines in the battle" for justice, peace and "authentic human rights."

However, he qualified, this commitment can only be effective "with the testimony of holiness."

Cardinal Ouellet made his remarks during a solemn Mass for the feast of Our Lady of Guadalupe celebrated at the Church of St. Mary in Traspontina, outside the Vatican.

The Dec. 12 Mass, concelebrated by cardinals, bishops and priests of the Roman Curia, was the closing event for the international congress Ecclesia in America, organized by the Pontifical Commission for Latin America and the Knights of Columbus.

The feast of Our Lady of Guadalupe celebrates the apparition of the Virgin Mary in 1531 to St. Juan Diego near present-day Mexico City. She told Juan Diego to ask the local bishop to build a church on the site. Later when he asked for a sign, she said his ailing uncle would be cured. She also asked him to gather in his tilma roses and other flowers which had miraculously bloomed.

When he unraveled his tilma before the bishop, it bore a miraculous image of the Virgin Mary in an indigenous style of art. The image helped convert many natives to Christianity.

Recalling the apparitions of Our Lady of Guadalupe, Cardinal Ouellet said, "Thanks to three miracles of Holy Mary, grace prevailed over episcopal prudence and marked the launching of the evangelization of the new world."

"But now she is urging the baptized of all of America to set out on the journey of the new evangelization," he said.

"We have come to Rome, to this meeting, guided by the star, like the 'wise men from the east,' the star that is Our Lady of Guadalupe," he told the more than 150 cardinals, bishops, priests and laity from across America and the Caribbean.

"Let us now bear witness to the Gospel that unites us beyond our borders and races in one continent, as children of the one Church: the entire world, especially the poor and those suffering most, await this testimony."

"We baptized should stand up and proclaim our faith with pride, certainly with respect for all but with the urgency of knowing that we must pass the torch of this faith on to the new generations of the digital culture," Cardinal Ouellet said.

He also spoke movingly about the testimony of holiness of the first saint of America, St. Rose of Lima, and that of the newest saint, St. Kateri Tekakwitha.  

"Both saints must be joining hands together in Heaven now, not only to watch over all of America, but also to urge us on in the new evangelization," he said.

"For this reason," the Canadian cardinal said, "the only guarantee that we have fulfilled our mission is holiness: the existence today of holy men and women."

"There is no obstacle to be saints today, a mustard seed of faith is enough," he said.