Pope Francis underlined the role of martyrs in the coming of "a new era of ecumenical commitment," telling Anglicans that the persecution of Christians for their faith only serves to strengthen Christian unity.
The head of the Roman Catholic Church made the statement on Thursday as he received 20 visiting members of the Anglican-Roman Catholic International Commission who visited the Vatican to study the relationship between the universal and local churches, the Official Vatican Network said.
"There is a strong bond that already unites us which goes beyond all divisions," Pope Francis told the delegation. "It is the testimony of Christians from different churches and traditions, victims of persecution and violence simply because of the faith they profess."
The Pontiff pointed out that the blood of martyrs, including those who were recently killed in the Middle East and the 45 Anglican and Roman Catholic "Martyrs of Uganda," will foster a new era of unity.
"And not only now, that there are many of them; I think also of the martyrs of Uganda, half Catholics and half Anglicans. The blood of these martyrs will nourish a new era of ecumenical commitment, a fervent desire to fulfil the last will and testament of the Lord: that all may be one," he said.
The Pope emphasized that the world needs the "common, joyful witness of Christians" on addressing social issues.
"Today the world urgently needs the common, joyful witness of Christians, from the defense of life and human dignity to the promotion of justice and peace. Together let us invoke the gifts of the Holy Spirit in order to be able to respond courageously to the 'signs of the times' which are calling all Christians to unity and common witness," he said.
He acknowledged that there are "new difficulties and challenges" between Catholics and Anglicans, but he did not specify any, the Catholic Herald reported.
"The cause of unity is not an optional undertaking" for any Christian community, said the Pope, adding that the "the differences which divide us must not be seen as inevitable. Some wish that, after 50 years, greater progress toward unity would have been achieved. Despite difficulties, we must not lose heart, but we must trust even more in the power of the Holy Spirit, who can heal and reconcile us, and accomplish what humanly does not seem possible."
The creation of the Anglican-Roman Catholic International Commission was the result of the historic 1966 meeting between Pope Paul VI and the Archbishop of Canterbury, Arthur Michael Ramsey, who inked a joint declaration to start dialogue based on the Gospel and the common tradition toward unity in truth.
Meanwhile, Pope Francis asked a group of elderly and sick people to pray for him because "I'm a little old and a little sick, but not too much."
The Pope on Sunday privately met with members of Rome's seaside parish where he received cheers and applause.
The 78-year-old Pope later celebrated a Mass at the Ostia parish, a beachfront area of the capital.
The Pope's latest comment on his health came two months after he said in an interview with a Mexican broadcaster: "I have the feeling that my pontificate will be brief – four or five years, even two or three. Two have already passed."
While Pope Francis appears to be in good health for his age, his condition has always been in focus considering that his predecessor, Pope Benedict XVI, resigned in 2013 citing his advanced age of 85 years and his frailty.
Benedict, now known as Pope Emeritus, became the first head of the Roman Catholic Church in 600 years to step down instead of ruling until he died.
Pope Benedict's move had the blessing of Pope Francis who said that it should not be considered "an exception, but an institution."