Kolkata, Aug 26 (IANS): Describing Mother Teresa as an "exemplary model of Christian virtue", Pope Benedict XVI has urged everyone to draw constantly from her spirituality and example in the service of the poor and the sick.

Sending his blessings from the Vatican on the occasion of Mother Teresa's birth centenary celebrations beginning Thursday, the Pope said he was joining spiritually to the celebrations.

In a message to Sister Prema, Superior General of the congregation Missionaries of Charity founded by Mother Teresa, the Pope expressed confidence that the centenary year will be for the church and the world an occasion of joyful gratitude to god for the "inestimable gift" that the Mother was in her lifetime.

"I send cordial greetings to you and all the Missionaries of Charity as you begin the centenary celebrations of the birth of Blessed Mother Teresa, founder of your Congregation and an exemplary model of Christian Virtue," he said in a message read out in a mass.

"I am confident that this year will be for the Church and the world an occasion of joyful gratitude to God for the inestimable gift that Mother Teresa was in her lifetime, and continues to be through the affectionate and tireless work of you, her spiritual children," the message said.

Mother Teresa exemplified love, the Pope said, and added: "May this love continue to inspire you as Missionaries of Charity, to give yourselves generously to Jesus, whom you see and serve in the poor, the sick, the infirm and the abandoned."

Giving his "paternal, apostolic Blessing" to the Missionaries of Charity and all those the Order served, he said: "I encourage you to draw constantly from the spirituality and example of Mother Teresa, and in her footsteps, to take up Christ's Invitation: 'Come, be my light."

The Albania-born nun, born Aug 26, 1910, took Indian citizenship and dedicated her life ministering to the poor, the infirm and the sick.

She came to India in 1929, set up the Kolkata-headquartered Missionaries of Charity 21 years later, and died here Sep 5, 1997. She was buried at Mother House, the global headquarters of her congregation here.

She was awarded the Nobel Peace Prize in 1979 and given India's highest civilian honour, Bharat Ratna, in 1980 for her humanitarian work. The Missionaries of Charity now comprises over 4,500 sisters and is active in 133 countries.

It runs homes for people with HIV/AIDS, leprosy and tuberculosis. It also conducts children's and family counselling programmes and runs orphanages and schools.