Yet the proceedings inside the 60,000-square-foot neoclassical structure will be a mystery to most outsiders - much like the faith itself.
Area Mormons will continue to worship in their local churches on Sundays, with the temple reserved for the most sacred rituals, or "ordinances." These include elaborate "endowment" ceremonies that bestow on followers the secret names by which God will call them on Resurrection morning.
It also will be the venue for initiation rites for the two orders of priesthood, "sealing" ceremonies that bind marriages for eternity, and baptisms for the spirits of the dead, usually performed in a pool set atop 12 life-size statues of oxen.
Not just any Mormon will have entrée.
A "temple recommend" from a hierarch is typically granted only to those adults active in their "wards," or congregations, and who tithe 10 percent of their income; eschew alcohol, tobacco, and caffeine; revere marriage and family; and fully subscribe to a theology well outside mainstream Christianity.
Membership growth impelled the decision to build the nation's 77th temple here, Mormon leaders say. Since 1990, the rolls of the baptized have gone from about 18,000 to 31,000 in the 45 counties of the new Philadelphia Temple District, encompassing the eastern half of Pennsylvania, all of Delaware, New Jersey's six southern counties, and portions of northern Maryland. The region has 90 congregations; about two-thirds have their own churches.
'Clarity of message'
Ahmad S. Corbitt, president of the Cherry Hill Stake, a diocese-like territory comprising South Jersey, attributes the growth to "shifting values [toward conservatism], maybe the clarity of our message, and our emphasis on individual salvation through Christ and the family."
Its hierarchy exclusively male, the Church of Jesus Christ of Latter-day Saints (LDS) claims a flock in this country of more than six million, concentrated in and around its Utah base. Worldwide membership is estimated at 14 million.
Although some scholars question those numbers, the church's official count makes it the fourth-largest denomination in the United States after the Roman Catholic, Southern Baptist, and United Methodist churches, and larger than the Episcopal and Lutheran churches combined.
The Philadelphia temple and a public visitors' center will draw more than 400,000 people a year to the city, LDS officials project. Mayor Nutter has said 300 construction jobs and 50 permanent jobs will be created, and "tens of millions of dollars of additional spending" channeled into the local economy.
Now, adherents must travel to New York's 20,000-square-foot temple, opened in 2002, or the 160,000-square-foot Washington temple, which in 1974 became the first on the East Coast. Some even journey to the central temple in Salt Lake City.
To those outside the faith, the Mormon presence in the Philadelphia area has most often made itself known with a knock on the door.
The new temple is unlikely to spawn more young missionaries here, said William Schaefermeyer, president of the Pennsylvania Philadelphia Mission, who oversees 180 "elders" and "sisters" recruiting from the New York state border to Virginia. In seeking converts, "it will be business as usual."
The sisters are typically assigned to the safer suburbs, said Schaefermeyer, but conversion rates are higher in poor, urban neighborhoods. "Just as in Jesus' time," he said, "the converts came from among the poor and humble, the people most susceptible to the Holy Spirit."
Despite its conservative morals and clean-cut ways, Mormonism is "poorly understood and poorly regarded by the American public," said Richard Phillips, a Mormon scholar and associate professor of religion at North Florida University in Jacksonville.
National polls show that Mormons "are viewed less favorably than any other major Christian religious group," he said, and "barely edge out Muslims" in public esteem.
In a Gallup poll in June, 22 percent of voters said they would not consider voting for Mormon presidential candidates Mitt Romney or Jon Huntsman. That figure is nearly four times larger than those who said they wouldn't pull the lever for a woman or an African American, and more than double the 9 percent who said they would not vote for a Jewish candidate.
Those are vexing numbers for those who have found a home in this young, unorthodox, and fast-growing faith.
"We're normal people," said Sister Sue-Haina Martha, 25, a Netherlands native six months into an 18-month assignment seeking converts in the Philadelphia suburbs. She is one of 50,000 missionaries worldwide.
"This religion is for everybody. . . . Jesus Christ is our center."
In late August, Martha was ringing doorbells in Wallingford, Delaware County, with 21-year-old Kristen Warner of Salt Lake City.
Well into their 14-hour workday, Gloria Stewart answered the door.
A retired Army officer, nutritionist, and longtime Baptist, she invited them in, listened, took their literature, and agreed to meet again.
In missionary lingo, Stewart had become an "investigator" - a prospect.
Early this month, they escorted her to a Mormon church in Broomall for a "sacrament service," where members are served bread and water and, lacking ordained clergy, give testimonies.
The following week, Martha and Warner were back at Stewart's garden apartment.
Seated across from her at the kitchen table, the younger women began with prayer and song.
"We will heed not what the world might say," they sang, then asked if Stewart had read the assigned passage from the Book of Mormon.
"Well," she said with a nervous laugh, "not all of it yet."
Talk soon turned to the Sunday service. "I enjoyed it," Stewart told them. "One of the sisters came up to me and made me feel so good."
It was a good enough sign for Warner to venture, "Can we call you 'Sister Stewart'?"
The older woman seemed surprised. "Well, yes," she replied. "That would be fine."
Did she understand the reading materials they had left last week? Martha asked.
"Yes," Stewart answered. "It was about Joseph Smith, how Christ told him not to join the other churches."
Mormon tradition teaches that in the early 19th century, the faith's founding prophet, then a child, had prayed fervently over which church to join. At 14, he was visited by Jesus and a human God the Father.
"None of them," Smith later said Jesus told him, because "all their creeds were an abomination."
Several years later, the Angel Moroni (pronounced "more-an-eye") revealed to Smith a book of golden plates buried in a hill near Smith's home in western New York 1,500 years earlier.
Beginning in 1827, at his father-in-law's farm in Pennsylvania's Susquehanna County, Smith spent more than two years translating the plates' "reformed Egyptian" into the 500-page Book of Mormon, telling of God leading the Lost Tribes of Israel to the Americas, and centuries of battles. In 1830, he and a small group of his followers founded what they called the Church of Jesus Christ.
"So, Sister Stewart," Warner asked, "how does that apply to you - that Jesus and God met Joseph Smith?"
"Well," Stewart said, "it's about what is really real. I'm not sure. . . ."
If she prayed about what she had read in the Book of Mormon, Warner told her, the Holy Spirit would "confirm in a quiet way that these things are true."
Then, another surprise.
"Will you follow the example of Jesus Christ," Warner implored, "and be baptized" - a full immersion at the church?
"Already?" Stewart asked.
"We have a baptism date available of Oct. 30," Warner replied. "We prayed about this, and we know you can be baptized by that day."
Stewart hesitated. "OK," she finally said. "Well, I have to read and reread to make sure I comprehend. I just read it but once."
"We'll teach you," Warner assured her, "so that you can enter the waters of baptism."
The missionaries assigned more passages to Stewart.
"I just have to read and pray for understanding to know if it's true," she said.
About 45 minutes after they had arrived, Martha and Warner finished with a prayer, hugged "Sister Stewart," and headed out.
Most other Christian denominations assert that Mormon theology isn't Christian.
On the contrary, the LDS avers, it alone teaches Jesus' message.
If Stewart continues toward baptism, she will learn the LDS teaches that human beings preexist in spirit form before their earthly births, that the God of this universe began bodily life as a human being, had "parts and passions," fathered children with his wife, and rules heaven and Earth as a physical being.
Anyone who is baptized can progress in the afterlife to become godlike, just as Jesus and God the Father did.
"We believe that as God once was, man will become," Elder Robert B. Smith of Downingtown, an overseer of the LDS in the Northeastern United States, explained in a recent interview. "After death, your spirit leaves your body" and "continues to learn."
During their time on Earth, Mormons are expected to marry and raise children, with whom they will live eternally. (This teaching explains some of Mormonism's antipathy toward homosexuality.)
Despite the lingering misperception that they practice "plural marriage" - Smith and his successor, Brigham Young, had dozens of wives - the LDS banned the practice in 1890.
Devout Mormons can, and typically do, baptize deceased relatives who were not Mormon, so the departed may choose to enter the path of "exaltation" in the next life.
Despite his unorthodox teachings and lifestyle, Smith had amassed 30,000 followers by 1844, when he was assassinated in an Illinois jail. By 1900, the church claimed a quarter-million members. By 1997, the global tally was 10 million. Today, 14 million.
Some religion scholars challenge those claims.
Young missionaries often rush prospects into baptism before they are knowledgeable or committed, said Phillips, the sociologist, yet the church continues for years to include dropouts on its rolls.
Although the LDS will not divulge the dropout rate, religion scholar and sociologist Armand Mauss of Washington State University has estimated 50 percent of U.S. converts drift away within a year. The overseas rate, he said, is probably 75 percent.
Whether Gloria Stewart will be among the 280,000 converts who the church projects will take the plunge into Mormonism this year is a question yet to be answered.
"All my family is Baptist," Stewart, a grandmother, said after the missionaries had left.
She is a member of White Rock Baptist Church in West Philadelphia, but she "had not gone recently," she said, because of a leg injury.
During that hiatus, the missionaries came to her door.
"I'm not sure I've had enough education" to convert so soon, "and the rituals I do not know," she said.
"But it is interesting."
Contact staff writer David O'Reilly at 215-854-5723 or email@example.com.