For 21 hours beginning at 2 p.m. today, this strifetorn Northeastern city hopes to experience something it has not had for years -- brotherly love.

Despite its motto, which many regard as sadly inappropriate, Philadelphians -- black, white and Hispanic -- say their city is desperately in need of a lifting of the spirit, the stock-in-trade of Pope John Paul II.

"No city in the nation . . . is more in need of the papal presence than Philadelphia," local columnist Claude Lewis wrote last week.

"The entire Delaware Valley region, for that matter, is in desperate need of a visit by the pope at this troubled time . . . He could stay here a month and still not reach the full measure of the problems we face," Lewis wrote.

Escalating crime rates, racial tension, a divisive mayoral race, a major federal law suit alleging widespread and systematic brutality by the city's police department, high unemployment, declining population, a failing public school system and a rickety public transportation network have all worked in recent years to keep this city in a funk.

On top of it all is an American Civil Liberties Union lawsuit against the use of city funds to pay for the massive altar platform that has been constructed for today's 4 p.m. papal mass at Logan Circle in center city.

Already, the suit -- and the predominance of Jews in ACLU leadership ranks -- have spawned a nasty wave of anti-Semitism.

"The hate mail is unbelievable," said Hilda Silverman, the organization's local director. "We've had death threats. What Jesus himself would find if he were coming here is all of these people who say they love the pope, but who stand ready to attack the Jews."

The pope, the Vicar of Christ, is coming. And for all of their fighting and fussing, spokesmen for the various and plentiful warring factions of this city say they are pleased.

Mayor Frank L. Rizzo, the object of much black and liberal scorn, has laid out the welcome mat. Blacks and Jews, ACLU suit notwithstanding, have been involved in the design and construction of the altar platform, which stands 28.5 feet and is 144 feet in diameter. City sanitation crews -- one archdiocesan wag said she "didn't believe they could work so hard" -- have done a reasonable job of cleaning up some filthy streets in the downtown neighborhoods the pope will visit.

Now, there is the waiting -- at Gate 55 in a secure corner of the Overseas Terminal at Philadelphia International Airport, where the pope's plane, Shepherd One, is to land; at Logan Circle, where an estimated one million worshippers are to attend mass and where 1,000 priests have been asked to help the pope distribute communion; and in Philadelphia's numerous back-street bars, where many an outcast patron will gather 'round to watch the pope on television.

John Paul will be greeted at the airport by 3,000 parochial school children, seated in a semicircle of bleachers when he steps from his specially fitted TWA jet. During a 30-second drum roll, 700 ninth graders from Cardinal O'Hara High School in nearby Springfield Township will hold up placards spelling out the words: "Philadelphia Welcomes Pope John Paul II With Love."

The O'Hara High greeting cards will be in English on one side and Polish on the other. The cards will be flipped on signal from Philadelphia's Cardinal John Krol.

The cardinal will then introduce Pope John Paul to Pennsylvania Gov. and Mrs. Richard Thornburgh (Episcopalians), Mayor Rizzo and his wife, Carmella (Roman Catholics), and to four auxiliary bishops.

(The Thorburghs and the Rizzos are among 2,000 secular and religious dignitaries who have been issued gold tickets by the archdiocese to attend a private reception with the pope before the 4 p.m. Logan Circle mass. Holders of the coveted gold and 18,000 silver tickets -- which also went to church and secular leaders -- will have reserved seating nearest the altar platform.)

After a brief choral and instrumental medley from the students, the pope will leave the airport in a White House limousine with a retractable bubble top. Weather permitting, the pope will stand in the limousine as he rides down Broad Street, the city's main thoroughfare, whose numerous potholes were recently filled.

The Broad Street route will take the pope's 10-car motorcade past hundreds of bands and thousands of the faithful from the 305 parishes that make up the five-county, 1.4 million-member Archdiocese of Philadelphia.

During the mass, the pope is expected to call for more religious vocations.

After his final blessing, which could come as late as 6 p.m., the pope will travel to Cardinal Krol's estate on City Line Avenue in Philadelphia's attractive Overbrook section. The pope, the cardinal and a small number of guests will dine on pepperpot soup, roast beef, Alaska salmon, and apple pie.

At 9 p.m. the pope will visit a familiar spot -- St. Charles Borromeo seminary in Overbrook, where he will lead a prayer service and attend a ceremony commemorating the visits he made to the seminary in 1969 and 1976 as Cardinal Karol Wojtyla of Krakow. He will return to Cardinal Krol's residence to spend the night.

At 7:30 tomorrow morning, the pontiff will travel to North Philadelphia to visit one of the city's largest Spanish communities and North Fifth Street's Church of St. Peter, where he will pray at the shrine of St. John Neumann.

North Philadelphia's Hispanic community, despite its poverty, spiraling unemployment rate, and grim physical environment, will offer John Paul a grand welcome.

Gold and white papal flags and bunting vie with the general drabness of the buildings from which they hang. Houses on North Fifth sport colorful signs reading, "Bienvenidos." The parish is spending about $15,000 to greet the pope.

"These people may be poor, but they are also friendly, warm and very proud. Their spirit hasn't been crushed by their many problems," said Father Thomas P. Graven, director of Casa Del Carmen, a Catholic organization serving the Hispanic community.

Philadelphia inner-city neighborhoods shift quickly from black to Italian, Italian to Irish, and Spanish to black and Eastern European.

For example, three blocks away from the poor parish of St. Peters is the beautiful, gold-domed Ukrainian Catholic Cathedral of the Immaculate Conception, also on the pope's schedule tomorrow.

He is expected to be greeted there by 2,000 Ukrainian rite Catholics, only 500 of whom still live in the immediate neighborhood.

At 9 a.m. tomorrow, John Paul II will say his second and final Philadelphia mass -- this one at the Philadelphia Civic Center for an estimated 17,000 priests, brothers and nuns.

He is scheduled to leave the city at 11:45 a.m.

Like columnist Claude Lewis, few here expect the papal visit to bring about social or political miracles.

The consensus, though, is that the pope's visit will engender hope.

"The pope is coming to Philadelphia and he is using the most simple of all things possible to convey the need for unity and brotherly love," said John Mosley, a black candidate for the priesthood.

"He is coming into this fractured city and inviting us all to the table, the altar, to share in the breaking of bread. Now, I don't care what you say, that is a beginning," Mosley said.