Pope Benedict XVI told parishioners that he wasn’t abandoning the Church by retiring to spend his final years in prayer, during his last Sunday blessing in the Vatican.

The 85-year-old pontiff will step down on Thursday evening, the first pope to do so in 600 years.

Tens of thousands of people packed into St. Peter’s Square for his final address, the New York Times reports.

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Police estimated some 100,000 people turned out to hear Benedict’s final weekly address.

He told the crowd that God was calling him to dedicate himself “even more to prayer and meditation,” which he will do in a secluded monastery.

“But this doesn’t mean abandoning the Church,” he said. “On the contrary, if God asks me, this is because I can continue to serve it (the Church) with the same dedication and the same love which I have tried to do so until now, but in a way more suitable to my age and to my strength.”

Benedict will make his final public appearance on Wednesday in front of a general audience in n St Peter’s Square.

No date has been set yet for the conclave of Cardinals, who will vote in secret to elect Benedict’s successor.

Meanwhile during a Mass in St Agnes's Church in Crumlin, Dublin, to mark the arrival of St John Bosco's relic, the Papal Nuncio to Ireland paid tribute to the Pope.

"I certainly have a degree of sadness in seeing Pope Benedict go into retirement because I have the greatest respect for him,’ he told the Irish Independent.

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Pope Benedict XVI gives his final blessing in RomeGoogle Images