VATICAN CITY — On his last morning in office, Pope Benedict XVI pledged today to respect and obey his successor and told the church’s cardinals that he would pray for them to be guided by the Holy Spirit in their selection of his successor.

“Among you is the future pope, to whom I promise my unconditional reverence and obedience,” the pontiff said, apparently trying to allay fears that having both a reigning and retired pope living inside the Vatican might spark confusion or division within the church.

Benedict bade farewell to the dozens of black-robed cardinals, the “princes” of the Roman Catholic Church, who were seated in the frescoed Clementine Hall of the Apostolic Palace. The prelates filed before him one by one to shake or kiss his hands and exchange a few words; many removed their red skullcaps out of respect.

In his valedictory remarks, delivered from his seat at the front of the hall, Benedict told the cardinals that it had been “a joy to walk with you in these years in the light of the presence of the resurrected Lord.”

Later today, the pope will be flown by helicopter to the papal summer retreat south of Rome, where he is likely to remain while the cardinals choose his successor in a conclave in the coming weeks.

At 8 p.m. today, Benedict’s resignation comes into effect and he ceases to be pope. He will continue to be addressed as “his holiness,” with the title “pope emeritus.”