The generation of Holocaust survivors, which is rapidly, 73 years after the liberation of the death camps, losing eyewitnesses, lost another powerful voice this week. Sam Bloch, who survived the Shoah because of the kindness of strangers (a Polish farming family that offered shelter to Mr. Bloch’s mother and brother) and the bravery of fellow Jews (the Bielski Brigade partisans who protected 1,400 Jews in the woods), died at 93.

Mr. Bloch, who spent his post-Holocaust years working in the vineyards of Holocaust remembrance, serving as an executive of the World Jewish Congress/Jewish Agency, and as a lay leader of a host of Jewish and Israel-centered organizations, kept the memory and lessons of the Holocaust alive in days when he was a minority in the survivor community. (Read his obituary here.)

In the first decades after the end of World War II, most survivors did not want to talk about what they had experienced in the camps and ghettoes and in hiding, and most outsiders had no interest in asking. This was before the NBC docu-drama sparked a spate of Holocaust memoirs, Holocaust studies at U.S. universities and a greater public interest in explaining the inexplicable.

Mr. Bloch, like his close friend Elie Wiesel, who died in 2016, understood the urgency of preserving the survivors’ memories before it is too late. He played a key role in organizing gatherings of survivors in Israel, Washington and Philadelphia, conferences that were part-reunion and part-celebration of life.

His death came during the week in which the president of Poland announced that he will sign a controversial bill, approved by the country’s parliament, which would make it a crime to assign Poland and Poles a role in the German-instituted Final Solution murder of millions of European Jews. The bill, whose debate in parliament coincided with Holocaust Remembrance Day in Poland and other European lands, is interpreted by many Jews as an endorsement of the kind of Holocaust denial that Mr. Bloch’s lifelong work opposed.

His prescience in writing his own memoirs and guiding the written works of other survivors helped guarantee that the Shoah will not be forgotten, and that his memory will be a blessing.