Israelis did not wait for yesterday's Yom Kippur ceremonies to begin acting in the spirit of the Jewish calendar's solemn Day of Atonement.
Ever since their government's invasion of Lebanon some citizens have questioned the aggression and sought to ameliorate the suffering of its victims. The invasion's horrible aftermath of civilian massacre increased the outcry. Last weekend hundreds of thousands protested against the performance of Prime Minister Begin and Defense Minister Sharon and demanded a full-scale investigation. On a percentage basis, it was as if more than 20 million Americans had marched on Washington.
Thus has begun the regeneration possible in a nation built on the principles of political democracy and humane religion. Some Arabs and others charge that militant Zionism, as exemplified in Israel's expansionist moves, has destroyed the traditional moral conscience of the Jews. This charge has to be given the lie by the display of Israelis' anguish over the massacre and their government's failure to clear the air about it.
Israel's American friends will recognize the ''workings of the system'' from their own Vietnam and Watergate days. Despite stone-walling in high places, such institutions as press, cabinet, legislature, loyal opposition, can operate to bring out the facts and proceed in accordance with them.
In Israel, even some members of the invading military forces have chosen to draw a line. Two months ago Col. Eli Geva resigned his brigade command rather than lead troops into west Beirut. Now he speaks of Israel as ''a country which is in a type of deterioration, or landslide, and everyone who believes in this country, has to contribute to stopping the landslide.''
The Israelis crying out for compassion, candor, and justice are surely making their contribution. They seem to be saying that, for all the tragedy brought about by others in Lebanon and elsewhere, Israel can judge itself by no less than its own best standards.
One result could be a reversal of the severe erosion of public support for Israel in its benefactor country, the United States. But, again, as Americans know from their own trial by fire in recent decades, any gain in esteem from outside pales in comparison with the self-respect that can come from a nation's living up to the ideals it has chosen for itself.