VATICAN CITY – Pope Benedict XVI on Friday lauded what he said was the “spiritual” nature of the nude figures that appear in Michelangelo’s masterpiece, “The Last Judgment.”

“As modern people … the (human) body appears to us as inert matter, as something heavy and opposed to knowledge and freedom inherent to the spirit,” Benedict said.

“But the bodies painted by Michelangelo are filled with light, life and splendor. He wanted to show that our bodies contain a mystery: within them the spirit is manifest,” the pontiff said.

The 84-year-old Benedict made the remarks in an address to members of the Vatican’s Pontifical John Paul II Institute for Studies on Marriage and Family, which, as the name suggests, was named after his predecessor John Paul.

“The Last Judgment,” a sprawling fresco that covers the altar wall of the Vatican’s Sistine Chapel, depicts among other scenes the biblical story of Adam and Eve, who are portrayed naked.

Benedict cited the story to reiterate Catholic teaching that sex should take place only within marriage between a man and a woman with the purpose of having children.

“The union in one flesh becomes a union for the whole of life, until a man and a woman become one spirit,” Benedict said. Sin, on the other hand, makes the body an instrument of “oppression of others, of the desire to possess and exploit.”