Pope Benedict XVI will address a group of parish priests from Rome on Thursday, a day after emotional scenes at his final papal mass in public in St Peter's Basilica before stepping down at the end of the month,
Vatican observers say the speech will be something like a "theological testament" that will form part of the legacy of the 85-year-old, who says his advancing age is preventing him from keeping up with the modern world.
Thousands of tearful priests, nuns and ordinary faithful applauded the pope at an emotional mass on Wednesday in which cardinals thanked the outgoing pontiff for his service and doffed their mitres in a sign of respect.
The pope waved and smiled at the crowd, appearing relieved following his momentous announcement on Monday, which will make him only the second pope to resign in the Church's 2,000-year history and the first to do so in 700 years.
His final homily was a hard-hitting one. He condemned the "hypocrisy" of those who use their religion just for show and urged an end to "rivalry" and "divisions" within a Church that has been plagued in recent years by a series of scandals.
The rumour mill over who could succeed Benedict is already in full swing. No clear favourite has emerged yet, but there are strong candidates across the world -- Africa, Asia, Europe, Latin America and North America.
The Vatican said the pope would speak at Thursday's meeting starting at 1030 GMT about his personal experiences as a young reformer at the Second Vatican Council of the 1960s, which changed the face of the Catholic Church.
Since then, Benedict has become far more conservative, trying to turn back the clock on more leftist currents in Catholicism. At the same time, he sought to rekindle the religious fervour of that time during his eight-year pontificate.
At his weekly general audience on Wednesday, the pope told thousands of cheering supporters that he was resigning "for the good of the Church.
"Keep praying for me, for the Church and for the future pope," he added.
The pope has said he plans to step down on February 28 and retire to a quiet life in a Vatican monastery, setting up an unprecedented situation in which a pope and his predecessor will live within a stone's throw of each other.
Vatican spokesman Federico Lombardi says the ex-pope -- who will revert to his previous name of Joseph Ratzinger -- could continue to provide some kind of spiritual guidance for his successor, but his role and title are still unclear.
The run-up to the resignation will be a combination of public engagements and private prayer -- with much of next week taken up by spiritual reflection during a period of penitence in the Christian calendar before Easter.
On the eve of his departure, the pope will hold an audience in St Peter's Square -- an event where thousands are expected to bid a final farewell to the contested but respected leader of the world's 1.2 billion Catholics.
The Vatican has said it expects the Conclave of Cardinals, meeting behind closed doors under Michelangelo's famous frescoes in the Sistine Chapel, to elect Benedict's successor by Easter, which this year falls on March 31.
The next pope will have to face up to the problems posed by rising secularism in much of the Western world; the need not just to stamp out the problem of clerical child abuse but to investigate thousands of past cases.
Another challenge to the Church as it moves forward is legislation being adopted in several countries to allow gay marriage. The new pope will also have to deal with shifting attitudes to divorce, abortion, the ordination of women and priestly celibacy.