Imitate Blessed John XXIII by growing in obedience to God and self-mastery to achieve peace, Pope Francis urged as he observed the 50th anniversary of his predecessor's death.

"If peace was the outward hallmark (of Pope John), obedience constituted his inner disposition," he said at Saint Peter's Basilica on June 3.

"Obedience, in fact, was the instrument with which to achieve peace," he told pilgrims from the Diocese of Bergamo, where John XXIII served before being chosen as pontiff.

The current shepherd of the diocese, Bishop Francesco Beschi, accompanied pilgrims from the northern Italian city, located 24 miles outside of Milan, to join Pope Francis in commemorating the anniversary.

After celebrating Mass with Bishop Beschi in St. Peter's, the faithful were addressed by Pope Francis, who had just spent a few moments in prayer at the tomb of his predecessor.

The Pope underscored that John XXIII's obedience led him to live "a more profound faithfulness, which could be called, as he would say, abandonment to Divine Providence."

Peace as his most "obvious aspect," Pope Francis underscored.

"Angelo Roncalli was a man who was able to communicate peace, a natural, serene, friendly, peace," he said of John XXIII.

"A peace that, with his election to the pontificate, was manifested to all the world and came to be called 'his goodness,'" he noted.

According to Pope Francis, that characteristic was "undoubtedly a hallmark of his personality, which enabled him to build strong friendships everywhere."

The bishop from Bergamo reigned as Pope for nearly three decades, and Francis noted how he was often in contact with people "far removed from that Catholic universe in which he was born and formed."

"It was in those environments that he proved an effective weaver of relationships and a good promoter of unity, inside and outside the Church community, open to dialogue with Christians of other Churches, with members of the Jewish and Muslim traditions," he said.

The pontiff noted he conveyed peace because he had "a mind deeply at peace, the fruit of a long and challenging work on himself."

"There we can see the seminarian, the priest, the bishop Roncalli struggling with the path to the gradual purification of the heart," the Pope said.

"We see him, day by day, careful to recognize and mortify the desires that come from his own selfishness, careful to discern the inspirations of the Lord," he remarked.

Pope Francis believes that his writings show "a soul taking shape, under the action of the Holy Spirit working in his Church."

He affirmed that his "prophetic intuition of convoking the Second Vatican Council and the offering of his life for its success, remain as milestones in the history of the Church of the 20th century and as a beacon of light for the journey that lies ahead."

Pope Francis exhorted the faithful from Bergamo to "keep his spirit, continue to deepen the study of his life and his writings, but above all, imitate his holiness."

"May he obtain for (the Church) from the Lord the gift of many holy priests, vocations to religious and missionary life, as well as to family life and lay commitment (to service) in the Church and in the world," he added.