JERUSALEM, NOV. 4 -- The senior boys at La Salle High School, in the Christian Quarter of the walled Old City, once again are gathering every morning at 8:20 for their first-period mathematics class, just as they had before the Temple Mount riots last month. But the boys are no longer the same.

At the front of the class these days stands an empty wooden desk, plastered with the same black and white handbill posted on the bulletin board and blackboard. On it is pictured Ibrahim Ali Farhat Khadik, 17, who, the text says, is "congratulated with love by his family" for becoming "a bride of Al Aqsa," the great mosque that stands on Haram Sharif, as Moslems call the Temple Mount.

On the morning of Oct. 8, Ibrahim and most of the 19 other Moslem boys in La Salle's 28-student senior class marched out of school and crossed the Old City to the Haram Sharif, ignoring the appeals of their teachers and parents that they avoid the demonstration called there by Moslem leaders. For most of these middle-class, private-school boys, it was their first direct experience of Israeli-Palestinian conflict, embarked on spontaneously in the exuberance of a crisp Monday morning.

None of them anticipated what would happen. A day they began with a picnic would suddenly explode into a frenzy of violence, turning them into combatants and confronting them with a sight that, even three weeks later, they describe in tones of shock and wonder: their friend Ibrahim being carried from the site in a blanket, shot dead, blood pouring from his mouth and chest.

Now, even as Israeli and Palestinian spokesmen continue to blame each other for the Temple Mount violence, La Salle's boys are drawing conclusions that speak of its real impact on the country. According to the final count by police and investigators, 17 Arabs were killed by police in clashes on the 35-acre site, and several Israelis were slightly injured when demonstrators threw stones from the nearby Western Wall, where Jewish worshipers were gathered for the holiday of Sukkot.

Of the 28 boys in La Salle's senior class Oct. 8, seven have since dropped out, with most giving the reason that they or their families are planning to emigrate. Another is in prison, held since the day of the violence on charges of stone throwing.

And five of the remaining 19 youths, who agreed to meet with a Western reporter after school recently, said they were all now willing to die fighting Israel.

"We all want to die like Ibrahim," said Ayman, a tall, thin 17-year-old with glasses. "Because it's something noble. It's like being a hero. And now we know the only way to achieve our aims is through violence."

Although such vows are extreme, these boys do not look or sound like the "Moslem fanatics" whom Israeli government ministers have insistently blamed for the Temple Mount conflict. Schooled in an elite institution operated by the Christian Brothers, they are polite and well spoken, able to express themselves in English and French as well as Arabic. Their parents are mostly professionals, and they are all planning to attend college. With their jeans, sport shirts and running shoes, they would easily blend into any American suburban high school.

Yet these youths seem buffeted against their bourgeois upbringing by the passions sweeping through Palestinian society. They can speak in the same breath of plans for medical school and "martyrdom," of their zeal for fighting Israel and dreams that Arabs and Jews will eventually live side by side in peace. They sometimes talk of Ibrahim in the sterile tones of nationalist rhetoric but can still let tears fill their eyes when they describe his bloodied body.

"These are the people that Israel will have to deal with, this young generation," said one of their teachers, Yasser Barakat. "And they are not like us, their parents. They have become much harder."

Three years ago, such Palestinian youths would never have joined a potentially explosive confrontation with Israeli police, for the simple reason that neither their parents nor their teachers would have allowed it. Yet as the three-year-long intifada -- or Palestinian uprising against Israeli rule -- has run its course, parents and other authority figures have steadily lost control over the youths, who have been the driving force of the rebellion.

That October morning, the boys now say, Ibrahim had started to go up to the Haram Sharif, only to be stopped by his father and redirected to school. But once he arrived at La Salle, he merely joined the other boys, who jointly decided to flout the standing rule prohibiting them from leaving campus.

"The whole school was buzzing, everybody was talking about the Jews who were going to march on our mosques," said Fadih, a chubby 17-year-old, referring to the planned march to the holy sites that day by an Israeli extremist group called the Temple Mount Faithful. "And we all just decided to go."

In the accounts of the La Salle boys, the Temple Mount violence appears as neither the planned provocation described by Israeli authorities nor as the massacre of innocents portrayed by Moslem leaders. For these boys, it was a sudden, shocking outburst that, once it gained momentum, stirred their own passions and drove them to do and see things they never imagined would happen when they set out from school in the morning. All of the five boys admitted gathering or throwing stones, although they said that up until the time the clashes started, they did not expect real trouble.

As the boys walked through the Old City that morning, passing nationalist graffiti that had been spray-painted on the stone walls of the Christian Quarter, "Ibrahim said to us, 'If I am killed, you can paint my name up there,' " remembered Nabil, a slight, curly-haired youth with the first traces of a mustache. "It was like a joke, but afterward it seemed like he had somehow foreseen his death. At the time no one took him seriously."

The boys said that none of them had heard about the planned demonstration until they arrived at school that morning. At that point, they heard what turned out to be an exaggerated account: that the Temple Mount Faithful planned to march to the Haram Sharif and lay the "foundation stone" for a new Jewish temple that would replace the Al Aqsa and Dome of the Rock mosques. In fact, the Jewish group had been prohibited by court order from laying the foundation stone, although police had planned to allow them to march into the Moslem-controlled compound.

When the La Salle students assembled on the Haram Sharif, they headed for a fountain where worshipers wash themselves before entering the mosques. There they heard a lecture delivered by a Moslem leader, who spoke "of what a good thing it is to be martyred" while fighting Israelis, Ayman said. "Ibrahim was very moved by it," said Nabil. "He became very excited."

Still, the schoolboys remained calm enough to move off to a shady area outside the Al Aqsa mosque for an impromptu picnic with the bag lunches they had brought to school. Sitting idly together, the boys talked about what might happen if the Temple Mount Faithful actually tried to enter the grounds, but figured there would not be major trouble, "because there were so few soldiers there," said Fadih. Only about 45 Israeli Border Police were on the Temple Mount to monitor about 5,000 assembled Moslems.

When the clashes suddenly started, near the Dome of the Rock mosque, "we were shocked and surprised, but not scared," said Nabil. He said many of the boys ran toward the Dome of the Rock, where they saw a masked Palestinian militant carrying a flag and leading a charge toward police. Nabil said he saw the man shot in the head after he grabbed a rifle from a policeman and tried to fire it. Most of the boys then retreated as fighting between the police and demonstrators grew heavy and tear gas filled the air.

Several of the students occupied themselves in the rear of the demonstration, filling trash barrels with stones and passing them up toward the front line. At one point, Ayman and Hamid, 17, were working together when Ibrahim came running back to them from the front. He had been wounded in the leg by a tear gas canister, and asked Hamid for a sweater. Then, grabbing a barrel of stones, he ran back toward the fighting.

"Most of us had never seen this before, soldiers and bullets, and did not want to get that close," said Fadih, who was also in the rear.

"But Ibrahim was more excited," said Ayman. "He was more patriotic. He felt he was a Moslem who wanted to defend the mosque."

The next time the three boys saw him, he was dead.

In the aftermath of the conflict, only one of the five boys who were interviewed said he believes Palestinians should aim at destroying Israel. The rest said they hoped for the creation of a Palestinian state in the Israeli-occupied West Bank and Gaza Strip that would coexist peacefully with the Jewish state. Still, the boys said the events on the Temple Mount had convinced them that there would be many more battles, and many more deaths, before any peace would come.

Hassan, a dark 16-year-old, was asked what plans he had for his future, in that case. "All of us will try to become martyrs like our friend," he replied, "and we will continue our education, too, because that's another form of struggle. Of course, if the situation stays like it has, it won't be easy for us to study. And there will be many more massacres."