THERE are about 8,000 men of all ages. They have come here from all over Iran to form a ``caravan to Karbala,'' the Iraqi city where Imam Hussein, the spiritual mentor of Shiite Muslims, is buried. These volunteers for a three-month tour at the front are parading through Tehran's streets before being dispatched to the battlefields, where they will back up Revolutionary Guards and regular Army units against Iraqi troops. Most of the would-be soldiers are in their 20s, some a bit younger. All share a fervent Shiite faith.
``The war against Saddam the infidel [Iraqi President Saddam Hussein] is holy, and I hope to be martyred to go to heaven,'' says Siamak, a young bearded man from the eastern city of Mashhad. Like his peers, Siamak wears a red headband. Red symbolizes the blood of martyrs.
Leading the cortege is a grizzled veteran whose two sons were killed in battle. He has brought along from his village a green flag with verses from the Koran on it. As the contingent winds its way down Tehran's main avenues, children rush to hug the departing combatants, while women sprinkle them with rose water and toss small pieces of sugar.
In downtown Tehran, the cheering crowd is so dense that local policemen struggle to clear a path for the caravan. Women wave pictures of relatives who have been killed at the front. Asked why she has tears in her eyes, one woman, Mahbubeh, answers, ``These are tears of joy. My son was martyred in 1981. Today my husband is going to the front. His only hope is to be martyred, and I hope God will fulfill this wish.''
This reporter tells Mahbubeh he can't understand this total submissiveness to God's will. ``Martyrs never die,'' she answers. ``Their spirits live among us. Every human being has to pass someday. And life here below is nothing, compared with the eternal paradise.''
The only Westerner in the crowd, this reporter walks by hundreds of demonstrators shouting anti-American slogans.
``Western journalists are liars,'' a man says. ``They keep on writing that our boys are forced to go to the front, which is untrue. They go there because they feel it is their Islamic duty.''
``You should tell [President] Reagan that we will never give up, and that we will destroy the Iraqi regime because it [invaded] us in 1980.'' (Iran and Iraq have been locked in a bitter struggle for the past 5 years, which has cost thousands of lives and millions of dollars in damage.)
After a moving farewell ceremony in front of the parliament building, the volunteers enter a barracks. Dozens of relatives cling to the surrounding fence, trying to catch a last glimpse of their beloved ones.
Zahra, a young chador-clad woman, bursts into tears. She was married just two months ago and fears she may never see her husband again. But she adds, ``God willing, we'll be victorious soon.''
Such scenes are now part of everyday life in Tehran, Western diplomats say. After recent military successes in the southwest front, Ayatollah Khomeini's government stepped up its drive to recruit volunteers for the front, the diplomats say.
``They're in a hurry to achieve a decisive victory over Iraq because of the country's worsening economic situation,'' a European ambassador says.
Declining oil prices have provoked a dramatic recession here. There are no real shortages, but average Iranians complain about the high cost of goods bought on the open market. Of course, every family is entitled to food coupons, with which it can buy basic commodities at very low cost. But many middle-class Iranians say the quality of government-subsidized food is poor.
During a two-week stay in Tehran, this reporter was struck by the frankness with which many Iranians from all social classes expressed opinions about their government in private converstaion.
The core of the regime's support seems to be among Tehran's populous southern neighborhoods. Residents there contend that, despite the economic problems, they're better off now than during the imperial regime of the Shah.
An Iranian sociologist disagrees: ``They say they're better off, but I don't think they really are.''
``But,'' he adds, ``this regime has rendered those poorly educated people aware of their traditional Iranian cultural identity. Under the Shah, those people would feel like strangers in their own country. Now they have the impression they have a say in the conduct of the country and their leaders speak their language.''
A bit north, in the city's business center, dissatisfaction is running high among bazaar merchants and their employees. The bazaaris -- private businessmen -- say Prime Minister Mir Hossein Musavi's ``leftist'' policies are killing the economy. Mr. Musavi favors a system that provides for food at low prices, price controls, rationing, and cooperative ventures.
An employee of the state-owned telephone company blames the bazaaris for ``pushing up goods prices by causing artificial shortages.''
Nevertheless, a vast majority of bazaaris remain staunch supporters of the basic principles of the Islamic Republic and say Iran has no alternative but to continue the war against Iraq until complete victory.
Discontent is also on the rise among civil servants who complain about the low level of their salaries.
But when it comes to discussing the results of the 1979 revolution that overthrew the Shah, most civil servants say it has brought positive cultural changes in their life.
Avowed opponents of the Islamic Republic itself can be found in upper-class Tehran neighborhoods. But Western observers agree that signs of active opposition to the regime have been fading.
``We're resigned,'' says Shahnaz, a middle-aged woman.
``We hate the mullahs, but they have built a strong regime and I doubt that exiled opponents will ever have the guts to kick them out.''
Many rich families are ruining themselves by changing money on the black market to pay for their children's studies abroad. The Iranian government has set up a strict exchange control, and only students who receive authorization from the Ministry of Education can purchase foreign currencies from Iranian banks. But dollars and German marks can be also bought from smugglers at six times their official rate.
Northern Tehran's landscape is also changing quickly. In the past few months, the government has been confiscating an increasing number of properties. These houses and apartments are often given or rented to poor families. Swarms of barefoot children wander in the once fashionable avenues.