Vayikra begins by laying down the laws of korbanos, the Temple offerings or "sacrifices" as colloquially [but quite inaccurately] translated. The second passuk details a few general disqualifications that limit what animals may be used for a korban in all types of korbanos. "Of the cattle" invalidates animals upon whom bestiality has been performed, "of the sheep" eliminates those animals designated for animal worship or those animals who had killed a person, and so on. The exclusions listed are specific to korbanos and are derived directly from the grammatical form employed [i.e. the word "of", such as in "of the sheep", implies that some of a given set of animals are acceptable, but not all.]
The very first disqualification that is learned from these pesukim, however, presents two difficulties. The very first passuk says, "a man who will offer up a korban", which is explained to teach us that, "just as the first man [i.e. Adam] did not offer stolen animals [as korbanos], for everything belonged to him, so too when you bring a korban, you may not bring a stolen [animal as a] korban."
This is doubly troubling. First of all, the prohibition of using stolen goods for the purpose of a mitzvah applies to all mitzvos and could have been taught in the context of any mitzvah. Why, then, would this universal disqualification be the first one listed for korbanos? Shouldn't something uniquely relevant to korbanos have been listed first? Secondly, at first glance it seems to be a stretch, contrived even, to assume that "adam - a man" refers specifically to Adam harishon and his ownership of all animals in the world. What does this seemingly far-fetched allusion mean?
In order to understand the unique impropriety of stolen korbanos, we must define the world of korbanos vis-a-vis all other mitzvos.
Imagine I hire a workman to fix something in my house and then discover that he used stolen goods to do so. Although I will be very upset and feel that he had committed a terrible wrong, his wrongdoing does not contradict the essence of our transaction. I paid him to fix something, and he did so. But now let us picture someone giving a close friend an expensive stolen item as a gift, or a chosson giving a kallah a stolen diamond ring. In these cases, the misdeed strikes at the heart of the very gift. The very essence of a gift is giving of oneself to another, i.e. taking the time and effort that I've invested in earning money and giving it to another in the form of a gift. The giving of oneself is totally absent when presenting a stolen gift, and thus such a gift has no redeeming value whatsoever.
The world of avodas Hashem has two major components: obligations and voluntary opportunities. Mitzvos are, first and foremost, commandments. A person who does a mitzvah, even if there are shortcomings in its performance, still has done his duty. But then there are korbanos, which are "offerings." Although some korbanos are obligatory, the quintessential korban is a voluntary offering, the equivalent of a "gift." This is evidenced by the fact that Rashi explains that the very first part of Vayikra is speaking specifically about a voluntary korban. This would indicate that the quintessential form of korban is indeed the voluntary gift, while the obligatory korbanos comprise a special subcategory. It therefore makes sense that the first disqualification listed for korbanos is a stolen korban, for this negates the essence of the korban. It is almost as if the passuk is meant to read, "if man offers of himself a korban", and if there is no "self" in the korban being offered, there is absolutely no korban to speak of. Offering a stolen animal is not an ancillary offense, or even the violation of a prerequisite; rather it is a distortion of what a korban is supposed to be! Adam was the only person in the world and thus its exclusive owner, and therefore his bringing a korban was, by definition, giving of himself, and that serves as the prototype of what a korban is supposed to be.
This gives us insight into why the nevi'im, when castigating Klal Yisroel for their sins, kept harping on their korbanos. For when a person is negligent in some of his duties, he is not excused from the rest of his duties, and certainly is not to be faulted for fulfilling them! If one does not wear teffilin, he will not be excoriated for wearing tzitzis! But korbanos are "extra-credit." As such, if a person is negligent in his basic obligations, and yet offers korbanos, the korbanos are seen as a cynical attempt to curry favor with Hashem instead of doing what is right. If we steal, act unjustly, and do not care for the weak, we are still doing what is right when we blow shofar and eat matzah; the wrongness of our misdeeds and the correctness of our miztvos are independent of each other. But when we dare offer "gifts" to Hashem while also engaging in wrongdoing, then the negative connotations of our misdeeds corrupt the korbanos themselves.
This is something to consider when we are engaged in activities that are lifnim mishuras hadin. As long as a person is focused on doing what is required min hadin, then his shortcomings do not directly affect his mitzvos. But if a person goes lifnim mishuras hadin in some areas while being grossly negligent in others, his lifnim mishuras hadin becomes a travesty and highlights his wrongdoings, chas v'shalom.