His work included the underground Hebrew-language publication Nitzotz, circulated in the Kovno Ghetto and Dachau concentration camp; the Israeli Labor Party newspaper, Davar; and other Hebrew, German, and English language writings.
Frenkel was active in an underground movement, "Irgun Brit Zion" (IBZ), founded in 1940 under Soviet rule.
Most of its members favored a moderate socialist approach, but the organization also included religious followers of Bnei Akiva as well as several Revisionists, who were more right-wing.
During this period, Frenkel was a member of the anti-Nazi resistance and helped to publish IBZ's underground newspaper, Nitzotz.
Together with other surviving residents of the ghetto, Frenkel was transported through Stutthof to a Dachau satellite camp, Kaufering; another train brought prisoners to Auschwitz.
He later described these circumstances: "The living conditions in the huts and tents, which absorbed moisture in autumn and winter, were much harder than in the ghetto, and it is hard to imagine how it was possible to undertake any Zionist activity after a one-kilometer march and twelve hours of forced labor" [6] In November 1944, Frenkel was transferred from Kaufering II to Kaufering I, where he was reunited with his father and the living conditions were somewhat better.
Before liberation, those issues were smuggled to safety, with the assistance of a Luxembourg priest who was interned in Dachau, Abbé Jules Jost, as well as a Spanish prisoner.
Nitzotz was published biweekly after the war and was the only Hebrew-language mouthpiece of the survivors (Hebrew :, She'erit Ha - Pletah').
There she rescued an almanac from the pre-war period, in which young members of IBZ (Ma'apilim), a group to which she had belonged, had collected memories and excerpts of Nitzotz .
Shafir is the author of two monographs and a large number of scholarly articles in anthologies and journals in English, German and Hebrew (see bibliography).
Since 1996, he worked as a research associate of the Friedrich Ebert Foundation in Israel, where he wrote as an expert adviser on the political situation.