Former President Bill Clinton and Sen. Hillary Clinton, D-N.Y., also attended the farewell ceremony, the New York Daily News reported.

Earlier in the day, the pope told a crowd at Yankee Stadium in New York that surrendering to love produces true freedom.

The leader of the world's Catholics, delivering his homily to the nearly 60,000 people who attended the papal mass, acknowledged that concepts such as "authority" and "obedience" are not easy to adhere to when society "rightly places a high value on personal freedom," The New York Times (NYSE:NYT) reported.

But, he said: "The Gospel teaches us that true freedom, the freedom of the children of God, is found only in the self-surrender which is part of the mystery of love. Only by losing ourselves, the Lord tells us, do we truly find ourselves."

Earlier, the pontiff blessed the site of the Sept. 11, 2001, terrorist attack on the World Trade Center. Pope Benedict knelt at Ground Zero and offered a prayer for peace, The Times reported.

"Turn to your way of love those whose hearts and minds are consumed with hatred," the pope said.

Pope Benedict briefly met with relatives of 16 of the people killed in the terrorist attack.

The day's events wrapped up Benedict's first visit to the United States since he assumed the papacy three years ago.