"The greatest among the greatest," a priest exulted over the loudspeaker as Pope John Paul II's limousine slid into view of crowds yesterday morning at Jasna Gora, site of Poland's holiest shrine.

Whether the priest meant John Paul was greatest among Poles or popes was never stated. But the point was clear nonetheless. The former archbishop of Krakow, Karol Wojtyla, is a hero to his countrymen, a figure already on a par with the leading names of Polish history: Copernicus, the scientist; Choplin, the composer; Paderewski, the pianist.

"He is a very great son of the Polish people," a Foreign Ministry functionary declared to an auditorium full of journalists the night before the pope's arrival.

"He is higher than any other Pole has been," said an older woman, resting from her shopping on a downtown bench in Czestochowa. "His is the highest authority."

She praised his warmth, his vigor. "We are all very proud of him," she said.

Four students just finishing high school, who traveled overnight by train for a glimpse of the pontiff, described him as "wise, reasonable," simpatico. "And besides," said one, he is a Pole and that is good for the soul, for patriotism."

For Americans, the notion of such hero worship may seem stilted, old fashioned. Neil Armstrong, the first man to the moon, the Lindburgh of our time, peddles cars on television. No one in U.S. public life today seems capable of inspiring anything like the awe here for John Paul II, not merely as the pontiff of the Roman Catholic church, but as a Polish inspirational leader.

A hero has been a long time coming for Poles. One of the larger, more populous countries of Europe, Poland has never had towering political personalities like a Napoleon, a Churchill or a Stalin. This pope, the first foreigner to reign in the Holy See in five centuries and the first Polish pope ever, has risen to eminence beyond anything a Pole has had before.

Pride, as one graduate student in Warsaw explained, "is something that Poles have always had in abundance but haven't always been able to exploit." In the center of Europe, on a main invasion route, Poland's sensibilities have been heavily influenced by France, Russia and Germany. "A person of John Paul's stature makes all Poles stand a little taller."

What's more John Paul II has shown from the outset that he intends to maintain the closest possible ties with his native land. On Easter Sunday, as he faced St. Peter's Square, the pope spoke in Polish "the only language which I really know," he said with a grin.

At the Vatican he has shared folk songs with Polish pilgrims. He has broadcast prayers in Polish on shortwave bands (a special thrill here where masses are not allowed on the radio).

Whether singing with the faithful or describing himself to delighted listeners as "the retired archbishop of Krakow," the pope at times seems more a politican on the hustlings than the heir to St. Peter.

In a Communist state like Poland, party leaders simply can't generate that kind of spontaneous rapport, whatever the leanings of the population. Wladislaw Gomulka, who ruled Poland from 1956 to 1970, was a dour man, an apparatchik. The present party chief, Edward Gierek, is amiable enough, but the stiff requirements of Communist authoritarianism don't make for displays of affection.

John Paul as a spiritual father to the Polish people, does not have to cope with their grievances about the economy and the other pitfalls of governing. In many ways, he is like a benevolent monarch, invested with popular reverence by virtue of his station, a moral force and a symbol of nationalism.

Naturally, there are those in Poland who find fault with the pope. His conservative views on abortion and theological questions makes him suspect on those grounds to more liberal-minded young people. Party loyalists and careerists want nothing to do with church affairs. But these, it seems fair to say, are not the majority in Poland today.

It is not for the substance of his office that John Paul is such a hero in Poland, not for his encyclicals or homilies. It is for his success and his grace.

"This is a great moment for Poland," said a woman factory worker this morning. And for a land like Poland, such greatness is to be cherished. CAPTION: Picture 1, COPERNICUS; Picture 2, CHOPIN; Picture 3, PADEREWSKI; Picture 4, JOHN PAUL II