Question: Our Gemara causes a difficulty for the explanation of the Riva in Pesachim (47b) who says that one should not be liable for plowing on Yom Tov as the dirt he plows is fitting to be used to cover the blood of a bird slaughtered on Yom Tov.

Question (cont.): The Riva asked, isn't Yom Tov both an Asei and Lo Sasei? He answered that even though Yom Tov is not pushed aside, one does not receive lashes for transgressing this prohibition. This is because the reason it is not pushed aside is due to the Asei, but the Lo Sasei is indeed pushed aside by the Asei of Kisuy ha'Dam.

Question (cont.): Our Gemara implies that as long as he did not transgress and take the bird there is an Asei and Lo Sasei present.

Answer: One must say according to the Riva's explanation that perhaps this (the Lo Sasei being pushed aside) is only regarding not receiving lashes on the Lo Sasei, but not that it is totally pushed aside.

Observation: The Gemara could have said he holds that he still has a chance to perform the positive commandment to send away the bird. This is why he receives lashes and sends away the bird according to the Rabbanan.

Observation: I explained this Gemara in Bava Metzia (102a).