The Pope's personal preacher has spoken out in praise – of the Reformation. He called for a renewed teaching by the whole Church of the Protestant doctrine of "justification by faith" as a means of countering modern "self-justification" through technology and science.

Father Raniero Cantalamessa, preacher to the household of Pope Francis, delivered his homily at Westminster Abbey, the Anglican flagship, in the presence of the Queen, Supreme Governor of the Church of England, who was present at the service.

The Reformation was the schism from the Catholic Church begun in the 16th century by Martin Luther and others. 

Father Cantalamessa said: "We should never allow a moral issue, like sexuality, to divide us more than faith in Jesus unites us.

"Nothing is more important than to seek Christ's heartfelt desire for unity."

Noting that the Christian world is preparing to celebrate the fifth centenary of the Reformation, he said it was "vital" not to remain prisoners of the past, arguing about who was right and wrong.

He was particularly enthused by the doctrine of "justification by faith" which was one of the principle articles of the Reformation and which means salvation is achieved by faith in Christ rather than by good works. He said it should be preached by the whole Church, not just the Protestants. 

"Justification by faith, for example, ought to be preached by the whole Church – and with more vigour than ever. Not in opposition to good works – the issue is already settled – but rather in opposition to the claim of people today that they can save themselves thanks to their science, technology or their man-made spirituality, without the need for a redeemer coming from outside humanity. Self-justification! I am convinced that if they were alive today this is the way Martin Luther and Thomas Cranmer would preach justification through faith." 

He also said it was important to put divisions in the past and be united in the face of Christian persecution. "In many parts of the world people are killed and churches burned not because they are Catholic, or Anglican, or Pentecostals, but because they are Christians," he said. "In their eyes we are already one. Let us be one also in our eyes and in the eyes of God!"

The Church of England has a special role in all of this, he added, calling on it to exercise an active function as a bridge between the Churches. "The presence among you of a priest of the Catholic Church, in circumstances of such special significance, is a sign that something of the kind is already happening."

One Church insider praised the homily, saying it could mark the dawn of a new era in relations between the two Churches. He said: "It is as if the Vatican has changed its Facebook status from 'it's complicated' to 'in a relationship'."