Pope Benedict XVI has promised "unconditional reverence and obedience" to his successor in his final greetings to cardinals before retiring.

 

Pilgrims and clergy hold a candle-lit vigil in Saint Peter's Square, facing Pope Benedict XVI's private apartment, after his final weekly public audience (Oli Scarff/Getty Images)

Benedict urged his cardinals Thursday to work in unity so that the College of Cardinals is "like an orchestra" where "agreement and harmony" can be reached — a clear message to the conclave that will pick the next pope.

He said he would pray for the cardinals in coming days and weeks as they choose his successor.

Around 5 p.m., Benedict will leave the palace for the last time as pontiff and fly to the papal retreat at Castel Gandolfo.

There, at 8 p.m. sharp, Benedict becomes the first pontiff in 600 years to resign. The doors of the palazzo will shut and the Swiss Guards will go off duty.