Rosh Hashanah 28 - Blowing a misappropriated shofar
If one takes a horn of an animal that has been consecrated as a burnt offering, he should not use it to blow the shofar on Rosh Hashanah. However, if he nevertheless did it, then the following sequence of events occurs: since he misappropriated a part of the offering, he transgressed and owes a sacrifice, but the horn, which he misappropriated, becomes his property. His blowing is now valid. By contrast, a peace offerings belongs in large part to its owner, and the laws of misappropriation do not apply to it. Thus, if he blew its horn, it remained in its consecrated status, and the blowing is invalid.
Another take from Rava: When does the misappropriation occur? - After he has blown the shofar! If so, all the time that he was blowing, the shofar was still the property of the Temple, and his blowing is invalid. Thus, in both cases it is invalid. Rava then reversed his opinion: in both cases the blowing is valid. Why? - The concept of benefit does not apply to mitzvot, but rather, they are a yoke on one's neck. Thus, there is really no benefit and consequently no transgression involved in either case, and in both cases his blowing fulfills the mitzvah.
Rava also said, "One who blows a shofar just for music's sake, has nevertheless fulfilled the mitzvah, since doing mitzvot does not require the intent." How could Rava say this? Didn't we learn that if one passes by the synagogue and hears the shofar, he fulfills the obligation - but only provided that he has the intent!? Answers Rava: "What kind of intent is meant? - to hear the shofar!" But that's exactly what the rule says!? - Rava meant, to hear the shofar as an instrument of music, and not imagine that it is braying of a donkey. What about the one who blows? He certainly knows that he is not a donkey but a human, blowing a shofar. - He is trying to make barking or some other unmusical sounds, and accidentally produces musical sounds.
Art: The Donkey by Eugene Joseph Verboeckhoven