TO JERSUALEM last week came an unusual group of pilgrims for a unique reunion, all survivors of the Holocaust and their families -- 4,000 of them from 23 countries joining another 1,000 victims of Nazi concentration camps who now live in Israel. Why now? Some participants said they hoped to bring the "lessons" of the Holocaust to a world that has known its share of more recent genocidal regimes since the destruction of Adolf Hitler's "Thousand-Year Reich." Anti-Semitism still flourishes in a number of countries, they pointed out, and there even exists in France and the United States a bizarre coven of neo-fascist polemicists devoted to spreading the malicious falsehood that the Nazis never murdered 6 milllion European Jews along with millions of Gypsies, Poles, Russians and others -- that the Holocaust, in short, was a myth. For those who survived the agnoies of Auschwitz and its counterpart camps, the fear that Western memory of the "Final Solution" has becoome gravely weakened provides reason enough to travel to Jerusalem -- bringing their children.

Many who came also brought with them documents, written memoirs and tape-recorded "oral histories" of their ordeal in the camps, all designed to bear witness to the numb, dismal suffering of those years, which cannot emerge in the televised attempts to recreate the crime through which the present generation comes to"know" the Holocaust. If their children alone could be made to understand the costs of endurance in the camps and the painful mixture of pride and guilt that often afflicted survivors, that and the memorial moments for those who perished lent the occasion special prupose.

But there was more. The gathering convened in Jerusalem at the very moment that Israel experienced the aftershocks and fallout of its raid on Iraqi nuclear facilities, a coincidence that lent an extra dimension -- possibly an uncomfortable one for some survivors -- to the occasion. They had listened earlier as Prime Minister Begin defended the raid as a step toward preventing an eventual atomic "Holocaust" directed against Israel. Later, Mr. Begin linked two quite distinct strands in the historical experience of Jews: the prophetic stress upon returning one day in triumph to the Holy Land and the emphasis upon survival itself.

Speaking at the Wailing Wall, site of the Roman destruction of the Second Temple in A.D. 70, Mr. Begin put it this way: "Where is the Emperor? Where is his might? Where is Rome? Jerusalem lives forever. We are here." He avowed that Israel had proved itself capable of outliving at least its ancient enemies.

But his final line, "We are here," reflected a particular tradition of Jewish belief that values above all else the moral virtue of personal endurance. As Mr. Begin's audience recognized immediately, the Yiddish version of the phrase "we are here" -- "Mir zaynen do " -- is the last line of an anguished song made famous during World War II when those walking to their deaths in the concentration camps sang it to affront their captors. The lyric urged Jews not to despair or to say they were leaving for the last time, because in the end they would persist: "mir zaynen do ." fThat sentiment, and not simply Mr. Begin's dismissal of historic enemies, is the telling legacy left to the rest of us in Jerusalem last week by those who managed the miracle of escaping the Nazi whirlwind.