The Palm Sunday rites kicked off the most solemn week in the Catholic Church, commemorating the passion and death of Christ and leading to the celebration of Easter a week later.
Explaining the significance of Palm Sunday, he said that in the time of Jesus, a soldier riding on a horse meant that he came to conquer, but when the Lord came on a donkey, it meant that he came in peace.
Catholic parishes and other places of worship, including those in city jails, became gardens of palm fronds on Sunday, April 14, as Holy Week began with the annual observance of Palm Sunday.
Jesus rode a donkey into Jerusalem.
Francis pointed to the story as a warning to resist triumphalism and remain humble.
"Festive acclamations and brutal torture: the silence of Jesus throughout his Passion is profoundly impressive", Francis said in his homily.
Francis added that "one subtle form of triumphalism is spiritual worldliness, which represents the greatest danger, the most treacherous temptation threatening the church".
After the blessing, the Pope, wearing red robes and cradling a braided palm, joined a procession to an open-air altar to celebrate Mass.
"I once again appeal to the young people and to all to pray for peace in the world, but especially for peace in the Holy Land and the Middle East", the pope said.
By the end of the ceremony rain was starting to fall but the crowd had swelled to 50,000 people, according to security officials.
REENACTMENT. Palm Sunday reenacts the triumphant entry of Jesus Christ into Jerusalem, as in this scene at the Baguio Cathedral on April 14, 2019.