Zevachim 14A

כל שאינו על מזבח החיצון כשלמים ⁠– אין בו משום פיגול!

that any offering whose blood is not sprinkled on the external altar like a peace offering is not subject to the halakhot of piggul? If so, piggul does not apply to inner sin offerings at all.

אלא הא והא רבנן, ולא קשיא; כאן בחטאות החיצונות, כאן בחטאות הפנימיות.

Rather, both this baraita and that baraita are in accordance with the opinion of the Rabbis; and the apparent contradiction between them is not difficult. Here, the baraita that maintains that one cannot render the offering piggul while dipping his finger in the blood is referring to the external sin offerings, since dipping one’s finger in order to sprinkle the blood on the external altar is not considered an essential rite. There, the baraita that maintains that one can render the offering piggul while performing this rite is referring to the inner sin offerings.

חטאות החיצונות ⁠– פשיטא, לא כתיב בהו ״וטבל״!

The Talmud asks: Isn’t it obvious that one cannot render the offering piggul while dipping his finger in the blood of the external sin offerings? The statement: “And the priest should dip his finger in the blood” (Leviticus 4:6), is not written with regard to these offerings. Since it is clearly not an essential rite, why was it necessary for the baraita to teach that improper intent while performing it cannot render the offering piggul?

אצטריך; סלקא דעתך אמינא: הואיל וכתיב ״ולקח״⁠ – ואי אתי קוף רמי להו אידיה בעי למישקל זימנא אחריתי ⁠– כמאן דכתיב ״וטבל״ דמי;

The Talmud answers: It was necessary for the baraita to teach this, as otherwise it might enter your mind to say that since it is written with regard to an external sin offering: “And the priest should take of the blood of the sin offering with his finger” (Leviticus 4:34), and therefore if a monkey comes and places blood on the hand of the priest the priest must take blood from the vessel again to perform the mitzva as stated in the verse, it is considered as though the statement: And the priest should dip his finger in the blood, is written with regard to an external sin offering as well.