If he’s talking about the epistle of Barnabas, its authenticity seems doubtful and contains a claim (false prophesy?) that the Romans were rebuilding the temple (cf 16.3-4). Not sure how this could be interpreted as an attack against the Jews (the biblical Barnabas was a Levite) anymore than the prophets did including Moses who went beyond upbraiding them but also slayed a few thousand in the wilderness.
