Kommentar zu Dewarim 14:20

כל עוף תאכלו ALL CLEAN FOWLS, YOU MAY EAT — but not (as is implied by these words) the unclean. Scripture intends, by this statement, to attach to the negative command which forbids unclean fowls (v. 12), a positive one which implicitly contains a prohibition. And similarly, when in the case of clean cattle it states, (v. 6) “that you may eat”, it implies: not, however, the unclean ones. Now a prohibition which is not plainly expressed but can only be drawn by inference from a positive command, is itself regarded only as a positive command, so that one who eats such food transgresses thereby not two negative commands, but a positive and a negative command (Sifrei Devarim 101:10; and cf. Rashi on Leviticus 11:3).

V. 20 כל עוף טהור וגו׳. Wir wagen die Vermutung, dass hierunter die erlaubten Heuschreckarten verstanden sein dürften (vergl. Chulin 139 b).

כל עוף טהור תאכלו, “you may eat every ritually pure bird.” According to the plain meaning of the text this includes certain species of locusts and grasshoppers not listed here by name.