וְכָל־יִשְׂרָאֵ֔ל יִשְׁמְע֖וּ וְיִֽרָא֑וּן וְלֹֽא־יוֹסִ֣פוּ לַעֲשׂ֗וֹת כַּדָּבָ֥ר הָרָ֛ע הַזֶּ֖ה בְּקִרְבֶּֽךָ׃ (ס)
et afin que tout Israël l’apprenne et tremble, et que nul ne commette plus un tel méfait au milieu de vous.
Sforno on Deuteronomy
וכל ישראל ישמעו וייראו ולא יוסיפו, neither the seducer himself nor others who found him convincing.
Tur HaArokh
ולא יוסיפו לעשות כדבר הרע הזה, “so that they shall not continue to commit such evils.” If the law against people preaching idolatry publicly or privately were not strictly enforced such a “disease” would become an epidemic.