Zevachim 2B

נדר הוא! אלא אם כמה שנדרת עשית ⁠– יהא נדר, ואם לא ⁠– נדבה יהא;

It is already referred to as a vow offering [neder]. Rather, the verse indicates that if you did what you vowed to do, i.e., you sacrificed your vow offering properly, it should be a satisfactory vow offering; and if you did not sacrifice it properly, it should be rendered a voluntary gift offering unrelated to the vow, and should not satisfy the obligation of your vow.

ונדבה מי שרי לשנויי בה?

The Talmud concludes: And is it permitted to deviate from protocol in the sacrifice of a gift offering ab initio? Clearly it is not. Evidently, even if one of the sacrificial rites was performed for the sake of sacrificing a different offering, it is still prohibited to perform any of the other sacrificial rites in the incorrect manner.

אמר ליה רבינא לרב פפא: לא הוית גבן באורתא בתחומא בי חרמך ⁠– דרמי רבא מילי מעלייתא אהדדי, ושני להו.

§ Ravina said to Rav Pappa: Since you were not with us last night within the Shabbat limit of Bei Ḥarmakh, you did not hear that Rava raises a contradiction between two superior mishnaic statements and teaches their resolution.

מאי מילי מעלייתא? תנן: כל הזבחים שנזבחו שלא לשמן כו׳. טעמא דשלא לשמן; הא סתמא ⁠– עלו נמי לבעלים לשם חובה; אלמא סתמא נמי כלשמן דמי.

What are these superior statements? We learned in the Mishnah: All slaughtered offerings that were slaughtered not for their sake are fit, but they did not satisfy the obligation of the owner. Rava infers: The reason they do not satisfy the obligation of the owner is specifically that they were slaughtered not for their sake. But if offerings were slaughtered without specification of intent, they, as well, satisfied the obligation of the owner. Apparently, if one performs any action without specification of intent, it is also considered as if he performed it expressly for its sake.