NOT long into Act I of “The Book of Mormon,” a new Broadway musical comedy written and composed by Trey Parker, Matt Stone and Robert Lopez, two young Mormon missionaries arrive in Uganda after an arduous journey from Salt Lake City, during which they have suffered a cramped flight and the theft of their luggage.

Their plight inspires the natives to burst into a joyous song, led by a Ugandan man who brightly introduces the missionaries to a population beset by famine, poverty and epidemic levels of AIDS, and who teaches them an African-sounding phrase that helps the locals forget their devastating troubles.

After crooning this phrase skyward for a few verses, the Ugandan man reveals to the missionaries that in English it translates to an obscene three-word oath. The third word, he says, is God.

The first two words? Well, they ain’t “Hakuna matata.”

This is the scene that Mr. Parker recently described as the “ ‘Welcome to Vietnam, wake up, O.K., we’re into the musical now’ number” of “The Book of Mormon”  the sequence that lets audiences know exactly what happens when you combine the talents of Mr. Lopez, a creator of the grown-up puppet musical “Avenue Q,” with those of Mr. Parker and Mr. Stone, who, as the masterminds of the adult animated series “South Park,” have a long history of tossing barbs at organized religion and having plenty more tossed back at them in return.