What is this Pasuk coming to teach us?
Rashi: It comes to add an Asei 1 to the Lo Sa'aseh against eating Tamei species of Sheretz ha'Of.
Ramban #1 (in Pasuk 3): It teaches us that all the above-listed birds are abhorrent and that all other species of birds are Tahor and are therefore fit to be eaten by a pure Nefesh.
Ramban #2 (citing R. Shimon in the Sifri): It comes to permit the Tahor species of locust, 2 whereas "ve'Chol Sheretz ha'Of ... " in the previous Pasuk is referring to the Tamei species of locust. 3
Rashi: Since a La'av that one extrapolates from an Asei is an Asei.
Ramban: Listed in Vayikra 11:22.
Ramban: Listed in Shemini Vayikra, 11:21. See Ramban DH 'u've'Sifri'.
