אִם־כְּמ֤וֹת כָּל־הָֽאָדָם֙ יְמֻת֣וּן אֵ֔לֶּה וּפְקֻדַּת֙ כָּל־הָ֣אָדָ֔ם יִפָּקֵ֖ד עֲלֵיהֶ֑ם לֹ֥א יְהוָ֖ה שְׁלָחָֽנִי׃
If these men die as all men do, if their lot be the common fate of all mankind, it was not the LORD who sent me.
How can Moshe say that if Korach and his followers aren't killed miraculously, then that means that Hashem didn't send him? Maybe Korach and his followers will do Teshuva and live!