The Gemara interpreted the expression "two living birds" in The Gemara interpreted the word "living" to mean those whose principal limbs are living (excluding birds that are missing a limb) and to exclude "treifah" birds (birds with an injury or defect that would prevent them from living out a year). The Gemara interpreted the word "birds" (, "zipparim") to mean kosher birds. The Gemara deduced from the words of "Every bird (, "zippor") "that is clean" you may eat," that some "zipparim" are forbidden as unclean — namely, birds slaughtered pursuant to The Gemara interpreted the words of "And these are they of which you shall not eat," to refer to birds slaughtered pursuant to And the Gemara taught that repeats the commandment so as to teach that one who consumes a bird slaughtered pursuant to infringes both a positive and a negative commandment.