More than just helping people in need, the Christian life must include the roots of charity, putting our entire lives at the service of Christ, as Mother Teresa did, Pope Francis said Sunday.

"The task which the Lord gives us ... is the vocation to charity in which each of Christ's disciples puts his or her entire life at his service, so to grow each day in love," the Pope said in his homily for the Canonization Mass of Mother Teresa of Calcutta Sept. 4.

It is estimated that there were 120,000 people in attendance at the Mass, according to the Vatican Press Office.

Referencing the question: "Who can learn the counsel of God?" in the Book of Wisdom, Francis said our task is to realize the call of God and then to do his will. But in order to do his will, we must first find out what it is.

"We find the answer in the same passage of the Book of Wisdom: 'People were taught what pleases you,'" he said.

What we are called to do, therefore, Pope Francis said, is "to translate into concrete acts that which we invoke in prayer and profess in faith."

Following Jesus is not for the weak, the Pope continued, but is a serious task, although one "filled with joy. It takes a certain daring and courage to recognize the divine Master in the poorest of the poor and to give oneself in their service."

The many volunteers and workers of mercy present in St. Peter's Square Sunday for the Jubilee of Mercy and for Mother Teresa's canonization are like the "large crowds" traveling with Jesus in the Gospel of Luke, the Pope said. They make visible Christ's concrete love for each person.

"How many hearts have been comforted by volunteers! How many hands they have held; how many tears they have wiped away; how much love has been poured out in hidden, humble and selfless service!" he said.

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Mother Teresa's life was given to this service. She was committed to defending life, especially the "unborn and those abandoned and discarded," Francis said. She was "a generous dispenser of divine mercy."

"She was committed to defending life, ceaselessly proclaiming that the unborn are the weakest, the smallest, the most vulnerable," he added. 

Just as Christ has bent down to help us, we must bend down to help the Christ found in those in need. "Wherever someone is reaching out, asking for a helping hand in order to get up, this is where our presence – and the presence of the Church which sustains and offers hope – must be."

Speaking of Mother Teresa, Pope Francis noted how she "bowed down before those who were spent … seeing in them their God-given dignity."

"Today, I pass on this emblematic figure of womanhood and of consecrated life to the whole world of volunteers: may she be your model of holiness!" he said.

"Let us carry her smile in our hearts and give it to those whom we meet along our journey, especially those who suffer. In this way, we will open up opportunities of joy and hope for our many brothers and sisters who are discouraged and who stand in need of understanding and tenderness."

After the Mass, Pope Francis continued immediately with praying the Sunday Angelus, first greeting and thanking everyone who took part, especially the Missionaries of Charity, whom he called the "spiritual family of Mother Teresa."

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He also greeted the various national delegations, pilgrims, volunteers and workers of mercy, and anyone who, through media, joined in the celebration from around the world.

"I entrust you to the protection of Mother Teresa: she teaches you to contemplate and adore Jesus Crucified every day, to recognize him and serve him in our brothers in need."

The Pope concluded his Angelus message by asking for prayers especially for Sister Isabel, 51, a Spanish missionary nun who was shot and killed Sept. 2 in Port-au-Prince, Haiti during what appears to have been a robbery.

Pope Francis prayed for an end to violence, and for greater security around the world.

"We also remember other Sisters that recently have experienced violence in other countries," he prayed, doing so "by addressing in prayer the Virgin Mary, Mother and Queen of all saints."