The City of Brotherly Love paused for a moment of prayer today after one of its worst weeks in recent history.

Special prayers were said, special offerings taken and special sermons delivered at places of worship across the city in an official day of prayer and mourning for the victims of a police assault and fire that left 11 dead and 250 homeless.

Mayor W. Wilson Goode described MOVE, the group whose row house was bombed, as "urban guerrillas" who were "bent on absolute destruction."

Goode read from a letter the city received from the group before last week's assault.

The letter warned that any attempt by authorities to remove the group from its compound in west Philadelphia would result in disaster because the organization was prepared to fight.

"It's goin' to be a mess. MOVE goin' to see to that, and the example that is left will be MOVE's favor," the letter said.

"If MOVE goes down, not only will everybody in this block be down, the knee joints of America will break and the body of America will soon fall," it said.

Goode and Gerald Ford Africa, a member of MOVE not involved in last week's events, appeared on the CBS television show "Face the Nation."

Africa maintained that the MOVE letter was not meant to be a threat but was designed to pressure officials to release nine MOVE members convicted of killing a city policeman in 1978.

"We did the safest, most practical thing possible to apply pressure without any bloodshed, without anyone being hurt," he said.

For Philadelphia, today was a day of soul searching, introspection, cleansing and quiet hope for the city.

Nowhere were services more poignant than at St. Carthage Catholic Church, a short distance from the two blocks and 53 homes destroyed by the fire.

When police evacuated residents in preparation for an assault on the row house headquarters of the radical group MOVE, St. Carthage threw its doors open to the displaced.

The church kept them open all week, offering food, shelter and clothing as life in most of the city returned to normal.

Today, several dozen of the homeless gathered under the eyes of network television cameras for a mass of "support and hope."

The Rev. Charles H. Diamond, the parish priest, a slender middle-aged man with steel-gray hair, told the congregation that the world is watching the Cobb Creek neighborhood of west Philadelphia.

"All of us have been through a great deal in the past week," he said. "The ordeal began one week ago today and for many it continues now and will continue for the foreseeable future.

"For those of you who have lost everything, remember that in having nothing you will be given everything . . . . Do not lose heart. People are concerned. People do love you. And people will help you.

"Don't believe what you read in the newspapers. I read a headline in the paper this morning that said, 'a neighborhood has vanished,' " Diamond said.

"This neighborhood has not vanished. Houses have burned to the ground. But this neighborhood is not houses. This neighborhood is all of us. We are together, and we will be together. We will rebuild," he said.

Goode, who called for the day of prayer and attended services at his Baptist church, said similar things all last week. But the words seemed to ring truer at the scene of the disaster.

The two blocks of row houses that burned were the kind of typical, middle-class neighborhood one finds in many American cities.

They were built to last in 1919 on the far western edge of the city. The style was colonial revival. Each had standard touches: hardwood floors, front porches, bay windows on the second floor, cornices and triangular pediments on the roof.

For years the neighborhood was Jewish. This began to change in the mid-1950s, and it is now predominantly black. The residents are solid and stable: schoolteachers, policemen, contractors, electricians, factory workers, government employes.

Fifty-three families have lost everything, and they are still shellshocked.

Thomas and Beth Mapp, who lived four doors from the MOVE headquarters on Osage Avenue and had hoped to celebrate their 25th wedding anniversary there last Tuesday, not only saw their home destroyed but lost all the pictures of their three children growing up and the 1960 Oldsmobile Super 88 they cherished.

Margaret Lane, sister of former basketball star Wilt Chamberlain, lived behind the Mapps on Pine Street. She lost her home and many of her brother's trophies.

"Why is the world, the nation, the city, so interested in us," Diamond said in his sermon. "When the cameras showed you, they showed a group of people that the world sees as themselves . . . . Those less fortunate than us saw their dreams going up in flames with your houses."

Many here have said a city is judged by how it responds to tragedy. Philadelphia has responded with an outpouring of donations of money, food and clothing and offers of assistance.