Before us is Mishnah 6, the final Mishnah in the third chapter of Tractate Zevachim. It too deals with thoughts that invalidate a sacrifice, and here we will encounter a Tannaitic dispute between the Sages and Rabbi Yehudah.
The view of Rabbi Yehudah and the disagreement of the Sages:
Rabbi Yehudah maintains that in addition to the thoughts already established as invalidating, during any of the four primary blood services - slaughtering, receiving, conveying, and sprinkling - if the one performing the service had a thought that, had it been carried out, would invalidate the sacrifice in its own right, then that thought invalidates the sacrifice in the same way that a thought to perform the service outside its proper place invalidates it. The Sages disagree and establish that the list of invalidating thoughts is short and defined: outside its proper time, outside its proper place, and not for its own sake - and even regarding the law of not for its own sake, this applies only to a sin-offering and a Passover-offering, and not to any other sacrifice. The halachah follows the Sages.
Therefore, the first part of the Mishnah lists thoughts that, had they been carried out, would invalidate the sacrifice, and according to Rabbi Yehudah they invalidate it even while they are merely a thought:
To leave the blood and not sprinkle it: The slaughterer or the kohen performing the receiving, conveying, and sprinkling, thinks to set the blood aside and not offer it at all. If he were to delay the blood beyond its proper time - meaning until nightfall of the day the sacrifice was slaughtered - this would become an issue of being left overnight, and the sacrifice would be invalid, and the one bringing it would not achieve atonement and appeasement.
Not to burn the sacrificial parts until tomorrow: The parts of the sacrifice must be burned on the altar on that same day, and when he sets them aside, their time expires.
To take the blood or the sacrificial parts outside the Temple courtyard: Their departure immediately invalidates them from being offered, and it is no longer possible to offer the sacrifice.
In all of these cases, Rabbi Yehudah says that the thought alone invalidates the sacrifice, like thoughts of outside its proper place. The Sages say that these thoughts are not on the list of invalidating thoughts, and they are nothing but foolish thoughts: if carried out, the sacrifice would indeed be invalidated, but the thought in and of itself does not invalidate it. The halachah follows the Sages.
A difficulty with the example of the sacrificial parts:
From a halachic perspective, if the blood was sprinkled on the altar properly, the sacrifice is valid even if the sacrificial parts were not burned, and the one bringing it achieves his atonement. If so, why does the Mishnah use the example of one who thought not to burn the sacrificial parts on that day, since actually carrying out this thought would not invalidate the sacrifice either?
One possible answer is that Rabbi Yehudah invalidates this by rabbinic decree: he is concerned that people might come to refrain not only from burning the sacrificial parts but even from sprinkling the blood. Therefore, even the failure to burn the sacrificial parts invalidates it by rabbinic decree, and consequently, even the mere thought not to burn them invalidates it by rabbinic decree. In any event, the halachah follows the Sages.
Thoughts that do not invalidate the sacrifice:
From here onward, the Mishnah lists thoughts that even if they were carried out, the sacrifice would not be invalidated in its own right. The first example is placing the blood on the ramp: although this is not a valid action, the actual placing of the blood on the ramp does not invalidate the sacrifice, since theoretically one could go back and receive new blood - lifeblood - if it is still available, and sprinkle it on the altar, and the sacrifice would be valid. It turns out that placing the blood on the ramp is similar to blood that was spilled, where there is a second chance, for it is as though he spilled it on the ramp instead of on the floor.
Therefore, even Rabbi Yehudah concedes that these thoughts, even though they are invalid thoughts in their own right, do not invalidate the sacrifice when he thought them during one of the blood services:
"Shechato al menas litno al gabei hakevesh" - He slaughters the animal with the intention to place its blood on the ramp. This is not a valid action, but it does not invalidate the offering on its own.
"Shelo keneged hayesod" - He intends to place the blood on the Altar, but not opposite the base.
"Liten es hanitan lematah lemaalah" - He intends to place the blood that must be placed below the red line, above the line.
"Es hanitan lemaalah lematah" - And vice versa: blood that must be placed above the red line, such as the blood of a sin offering, he intends to place below the line.
"Es hanitan bifnim bachutz, ve'es hanitan bachutz bifnim" - He intends that what must be offered on the outer Altar will be offered on the inner Altar, or that blood to be placed on the inner Altar will be placed on the outer Altar.
"Sheyochelohu temaim" - He intends at the time of slaughtering, receiving, or sprinkling the blood that the meat of the offering will be eaten by ritually impure kohanim. This is prohibited, but it does not invalidate the offering.
"Sheyakrivuhu temaim" - He intends that the emurim and the parts to be offered will be offered on the Altar by ritually impure kohanim. This too is prohibited, but does not invalidate the offering: once the blood reaches the Altar the offering is valid, even if the parts were not offered properly, and the one bringing it achieves his atonement.
"Sheyochelu areilim" - He intends that uncircumcised men will eat the meat. This is prohibited by Torah law, but does not invalidate the offering.
"Sheyakrivu areilim" - He intends that the parts to be offered will be offered on the Altar by uncircumcised men. This is prohibited, but does not invalidate.
"Leshaber es atzmos hapesach" - Regarding the Passover offering, stringencies and Torah commandments were stated concerning the manner of its eating, including the prohibition to break its bones. If he slaughtered it with the intention to break the bones to extract the marrow, this is a foolish intention, and if he executes it he will violate a negative commandment - but the Passover offering itself is not invalidated, and the rest of the group, as well as he himself, remain in a valid state, only that he has transgressed a separate prohibition.
"Vele'echol heimenoo na" - He intends to eat from the Passover offering when it is raw, even though it is prohibited, as it must be roasted over fire.
"Le'arev damo bedam pesulim" - He intends to sprinkle the blood on the Altar while it is mixed with invalid blood. This matter is more complex, and we will expand on it below.
In all these cases the Mishnah rules "kasher" - the intention alone to perform one of these prohibited or futile actions does not invalidate the offering. As the Mishnah states: "She'ein hamachashavah poseles ela chutz lizmano vechutz limkomo, vehapesach vehachatat shelo lishman" - the invalidating intention, certainly according to the Sages, is the one that the offering will be eaten by man or consumed by the Altar at the wrong time or in the wrong place; and regarding the Passover offering and the sin offering - also the intention for another offering, not for its own sake. The halachah follows the Sages.
"Le'arev damo bedam pesulim" - the approach of Rabbi Yehudah regarding a species mixed with its own species:
It is prohibited to offer on the Altar blood that has been mixed with invalid blood. Seemingly, there was reason to say that Rabbi Yehudah would invalidate this, for since it is impossible to do so and the matter is invalid, this is an invalidating action, and consequently even the intention about it would invalidate everything. However, Rabbi Yehudah has a general approach, and not only regarding this matter: a mixture of valid blood with invalid blood is a mixture of a species with its own species - a mixture of two things of the same kind, blood with blood, even though one is valid and the other is invalid.
In every mixture, the rule is that the minority loses its identity within the majority, and the entire mixture is judged with one law that follows the majority - this is nullification by the majority. But the approach of Rabbi Yehudah is that in a mixture of a species with its own species, the minority is not nullified. Therefore, even if there are nine parts, or ninety-nine parts, of invalid blood and one part of valid blood, the valid blood stands in its place and does not disappear. Consequently, when the mixture is placed on the Altar - even though this is prohibited by rabbinic law - by Torah law he fulfills his obligation, since the blood reached the Altar.
It emerges that according to the Sages, even though carrying out the intention in practice would invalidate the offering - as in any case one must not do this, and it is possible that he would not fulfill his obligation at all when the valid blood is a minority - nevertheless, intentions of this type are not considered significant and do not invalidate. And even Rabbi Yehudah, who holds as stated that an intention whose practical execution invalidates the offering invalidates on its own, concedes here that the intention does not invalidate: since in a mixture of valid blood and invalid blood the valid part is not nullified even when it is a minority, thus if he sprinkles the blood on the Altar - even though by rabbinic law it is prohibited for him to do so - he fulfills his obligation after the fact, and therefore the intention does not invalidate.
In summary: In this Mishnah we learned the dispute between the Sages and Rabbi Yehudah regarding the law of invalidating intentions. Rabbi Yehudah adds any intention whose practical execution would invalidate the offering on its own, such as delaying the blood until it is left overnight, not burning the emurim, or taking the blood and the emurim outside the Courtyard. The Sages establish a short and defined list: outside its time, outside its place, and for the Passover and sin offering also not for their sake, and the halachah follows them. We also enumerated the intentions that even Rabbi Yehudah concedes do not invalidate - placing the blood on the ramp and not opposite the base, changing the place of placement above and below and inside and outside, eating and offering by ritually impure and uncircumcised men, breaking the bones of the Passover offering and eating it raw - and finally we addressed the law of mixing the blood with invalid blood and the approach of Rabbi Yehudah that a species mixed with its own species is not nullified.