In one of his final addresses to the Jewish nation, Moses exhorts them to remain true to God (Deut. 18:13): “You must be perfect with God your God.”
The medieval commentaries debate whether this is an actual commandment issued in the context of the preceding verses, or whether it is simply a warning that the Jewish nation should remain true to themselves, and not contaminate their perfection with foreign ideas and concepts.
Rabbi Dunner shares the interpretations of Rambam and Ramban, but also offers a range of more recent understandings of this verse, including those of R. Zvi Elimelech Spira of Dinov and the Seer of Lublin, who see it in isolation, a unique appeal for Jews to shine and excel in a world that militates against faith and belief.