Pope Benedict XVI has given his final Sunday blessing from his studio window to the cheers of tens of thousands of people in St Peter's Square, Rome.
Benedict said that even though he is retiring on Thursday from the papacy, the first pope in 600 years to do so, he is "not abandoning the church".
Instead he said he will serve the church with the same dedication he has until now, but will do so in a way "more suitable to my age and my strength".
Benedict, 85, will spend his last years in prayer, meditation and seclusion in a monastery on Vatican City's grounds.
He has one more public appearance, at his weekly audience on Wednesday in the square.
Benedict has lately looked tired and frail but the crowd filling the cobblestone square seemed to energise him, and he spoke in a clear, strong voice, repeatedly thanking the faithful for their closeness and affection as they interrupted him, again and again, with applause and cheers.
Police estimated some 100,000 people turned out.
Benedict told the crowd that God is calling him to dedicate himself "even more to prayer and meditation", which he will do in a secluded monastery being renovated for him on the grounds behind Vatican City's ancient walls.
"But this doesn't mean abandoning the church," he said, as many in the crowd looked sad at his departure from regular view. "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."
The phrase "tried to" was the pope's ad-libbed addition to his prepared text.
Benedict smiled at the crowd after an aide parted the white curtain at his window, telling the people, "thank you for your affection".
Heavy rain had been forecast for Rome, and some drizzle dampened the square earlier in the morning. But when Benedict appeared, to the peal of church bells as the clock struck noon, blue sky crept through the clouds.
"We thank God for the sun he has given us," the pope said, sounding cheerful.
As cheers continued in the crowd, the pontiff simply turned away from the window and stepped back down into apartment, which he will leave on Thursday, taking a helicopter to theVatican summer residence in the hills outside Rome while he waits for the monastery to be ready.
A child in the crowd held up a sign on a yellow placard, written in Italian, "You are not alone, I'm with you." Other admirers held homemade signs, saying "Grazie".
No date has yet been set for the start of the conclave of cardinals, who will vote in secret to elect Benedict's successor.
One Italian in the crowd seemed to be doing a little campaigning, hoisting a sign which mentioned the name of two Italian cardinals considered by observers to be potential contenders in the selection of the next pontiff.
Flags in the crowd represented many nations, with a large number from Brazil.
The cardinals in the conclave will have to decide whether it is time to look outside of Europe for a pope.