Rome (CNN) -- Benedict XVI pledged "unconditional obedience" to the next pope in his final meeting with the cardinals who will pick his successor after he stands down later Thursday.

"I will continue to serve you in prayer, in particular in the coming days" as the cardinals work to select a new pontiff, he said.

After nearly eight tumultuous years at the head of the world's 1.2 billion Catholics, Benedict XVI has made the almost unprecedented decision to resign effective 8 p.m. (2 p.m. ET).

His words to the cardinals appeared designed to answer concerns that the presence of a former pontiff might lead to confusion or competing loyalties once the new pope is installed.

Benedict told the cardinals it was a "joy to walk with you" during his eight years as pope.

Vatican spokesman the Rev. Thomas Roscia said he believed 144 cardinals had attended Benedict XVI's farewell to them as pope.

That includes both cardinal-electors, who are under the age of 80, and cardinals who are not eligible to vote for the next pope. Not all those eligible to vote were present, said another Vatican spokesman, the Rev. Federico Lombardi.

There are 115 cardinals eligible to vote for the next pope, he said. Two cardinals are suffering ill health, making their attendance uncertain, although arrangements may be made to enable them to vote, Roscia said.

The new pope is almost certain to come from within the cardinals' ranks.

In their meeting Thursday morning, the cardinals gave Benedict a standing ovation, and then one by one each met the pope to say a final few words.

Cardinal Roger Mahony, the retired archbishop of Los Angeles, tweeted after the event that he had asked the pope to pray for the people of Los Angeles.

"He grasped my hand and said 'Yes'!!" Mahony said.

The current Catholic archbishop in Los Angeles earlier this month disciplined Mahony for his mishandling of "painful and brutal" allegations of sexual abuse by priests. Mahony's decision to travel to Rome to take part in the election of the new pope has been controversial because of that.

Benedict's last day in office has been carefully mapped out by Vatican aides who've had to make up the rules over the past two weeks.

In contrast to the public focus of his final general audience and meetings with foreign dignitaries Wednesday, Benedict is spending Thursday in a quiet, more intimate manner.

Later, senior Vatican officials and a detachment of the Swiss Guards, who by tradition protect the pope, will gather to bid him farewell as his helicopter takes off from Vatican City bound for the summer papal residence, Castel Gandolfo.

Once at Castel Gandolfo, where he will spend the next few weeks before moving to a small monastery within the Vatican grounds, Benedict will make one last public appearance on the balcony.

Having greeted those gathered below, he will step back inside and begin his life of seclusion.

At 8 p.m., the Swiss Guards will ceremonially leave the residence's gate and seals will be placed on entrance to the pope's Vatican apartment, the Vatican said.

The pope has the right to wear the symbolic Fisherman's Ring until 8 p.m., Lombardi said.

After that the ring and Benedict's papal seal will be "destroyed" by means of making scratch marks so that they can no longer be used to seal documents, he added.

The process of transition to a new pope will then begin.

The Vatican has said it wants to have the next pontiff in place in time for the week of services leading up to Easter Sunday on March 31.

A series of meetings to set the timetable for the conclave -- the secret election of the new pope -- will begin as of next week and the cardinals need to prepare, said Lombardi.

They will receive the formal invitation to attend on Friday, he said.

Cardinal Gianfranco Ravasi of Italy, tipped as a possible future pope, tweeted Thursday morning that he would be away for a few days.

A number of other cardinals, including Ghanaian Peter Turkson, also considered a frontrunner, and New York's Timothy Dolan are also present on Twitter.

Cardinals are forbidden to communicate with the outside world -- now including by Twitter -- during the conclave, held within the Sistine Chapel.

The Vatican declined to say whether BlackBerrys, iPhones and laptops would be taken away from cardinals when they are in the conclave.

There is no Internet access inside Santa Marta, where the cardinals will stay during the conclave, Lombardi said.

Benedict will send his final tweet Thursday afternoon Rome time, and then the account @Pontifex will go dormant until the next pope decides whether he wants to use it, Lombardi said.

Benedict will not get any advance notice of who his successor will be, Roscia said. The pope emeritus will find out who has been elected at the same time as the rest of the world.

Mired in scandal

His resignation opens up the prospect of unforeseen opportunities and challenges for the Roman Catholic Church.

Many are wondering whether a new pontiff will choose to lead the church in a different direction -- and can lift it out of the mire of scandal that has bogged down this pope's time in office.

Even as Benedict's final week began, Vatican officials were trying to swat down unsavory claims by Italian publications of an episode involving gay priests, male prostitutes and blackmail. Then the news broke that Benedict had moved up the resignation of a Scottish archbishop linked over the weekend by a British newspaper to inappropriate relationships with priests.

Last year, leaks of secret documents from the pope's private apartment -- which revealed claims of corruption within the Vatican -- prompted a high-profile trial of his butler and a behind-doors investigation by three cardinals. Their report, its contents known so far only to Benedict, will be handed to his successor to deal with, the Vatican said.

At the same time, the church faces continued anger about what many see as its failure to deal with child sex abuse by priests.

So, when Benedict announced on February 11 that he would step down, becoming the first living pope to resign in 598 years, there was inevitable speculation that his move was in some way linked to the brewing scandals.

The danger for the Vatican is that the furor risks overshadowing what others see as Benedict's real legacy to the church: his teaching and writings, including three papal encyclicals.

Proof of the Vatican's irritation came with a stinging statement Saturday complaining of "unverified, unverifiable or completely false news stories," even suggesting the media is trying to influence the election of the next pope.

The constant buffeting by scandal will doubtless also have taken a toll on an 85-year-old man whose interests lie in scholarly study and prayer rather than damage control.

Benedict suggested as much at his final general audience Wednesday, when in front of cheering crowds in St. Peter's Square he spoke of steering the church through sometimes choppy waters.

There had been "many days of sunshine," he said, but also "times when the water was rough ... and the Lord seemed to sleep."

The pope also called for a renewal of faith, and for the prayers of Catholics around the world both for him and his successor.

Although his departure leaves the church facing many questions, Benedict suggested that its future, "at a time when many speak of its decline," lies in seeing it as a community of many people united in a love of Christ, rather than as an organization.

Tweeting Wednesday on his @Pontifex Twitter account, the pope said: "If only everyone could experience the joy of being Christian, being loved by God who gave his Son for us!"Pope Benedict Says Final Goodbyes