"What would the Church be without you?" the Pope told the women May 8. "It would be missing maternity, affection, tenderness and a mother's intuition."

Religious superiors, Pope Francis said, need to ensure their members are educated in the doctrine of the Church, "in love for the Church and in an ecclesial spirit."

Quoting Pope Paul VI, he said: "It's an absurd dichotomy to think one can live with Jesus, but without the Church, to follow Jesus outside the Church, to love Jesus and not the Church."

The sisters, who came from 76 countries, were in Rome for the plenary assembly of the International Union of Superiors General. The group welcomed the Pope with loud applause and with the ululations of the African sisters among them.

Sr. Mary Lou Wirtz, superior of the Daughters of the Sacred Hearts of Jesus and Mary and president of the International Union of Superiors General, said the sisters "are very pleased with the Pope, and it gives them hope of maybe some change happening in the Church." They appreciate the Pope's emphasis on serving the poor and going out to the margins of society, "because that's what our service as religious women is about."

In his talk to the women, Pope Francis said their vow of chastity expands their ability to give themselves to God and to others "with the tenderness, mercy and closeness of Christ."

However, "please, let it be a fruitful chastity, a chastity that generates sons and daughters in the Church. The consecrated woman is a mother, must be a mother and not a spinster," he said. While the sisters were laughing at his use of a very colloquial Italian word for "spinster" or "old maid," he added: "Forgive me for speaking this way, but the motherhood of consecrated life, its fertility, is important."

Pope Francis said that just as Mary could not be understood without recognizing her role as being Jesus' mother, the Church cannot be understood without recognizing its role as being the mother of all believers. "And you are an icon of Mary and the Church," he said.

The Pope said every vocation — and not just a call to the priesthood — begins with a call from God and is a call to continually centre one's life and actions on Christ, "adoring the Lord and serving others without holding anything back for oneself."

But particularly for priests and religious, responding to that vocation means feeling, thinking and acting in communion with the Church "that generated us through baptism," he said. "The proclamation and witness of the Gospel — for every Christian — are never isolated acts. This is important," the Pope said, repeating the phrase and adding that Christians do not do good because of a "personal inspiration, but in union with mission of the Church and in its name."

For members of religious orders, the whole process of growing in love and dedication to Christ and in service of others is aided by poverty, chastity and obedience, Pope Francis said. Embracing poverty, he said, means overcoming all temptations of selfishness and instead relying totally on God's providence. It is expressed in simplicity and learned from living with "the humble, the poor, the sick and all those on the existential margins of life."