As we have learned on yesterday’s daf, sacrifices that were kodashei kodashim – the holiest of holies – were brought in the northern part of the Temple courtyard. The source for this law appears in the Torah with reference to the korban olah – the burnt-offering – and the other sacrifices were derived from the olah.
The Gemara on today’s daf asks why the korban asham – the guilt-offering – needs to be compared to both the korban olah and the korban ḥatat – the sin-offering (see Vayikra 14:13 where the Torah requires that the asham be slaughtered in the same place as the ḥatat and the olah).
Ravina explains that if the Torah’s comparison connected the asham with the ḥatat, this may have led to a mistaken conclusion that a law derived by means of a hekesh (a word analogy) – like the law that the ḥatat must be slaughtered in the northern part of the Temple courtyard, which is derived from the clearly stated law regarding an olah – can then be used to teach that law in a similar situation – like using ḥatat as a source for the law for the korban asham.
In truth, in this particular case it is likely that we would have been able to derive the law of the asham from the law of the ḥatat, even though the ḥatat is not the original source of the law. This is because (as we learned on yesterday’s daf) the Torah clearly states that the ḥatat must be slaughtered in the same place that the asham was slaughtered, so it is not an ordinary hekesh, it is almost a biblical source. Nevertheless, because of the possibility that someone might mistakenly think that this law is derived from a hekesh and is used as a source for another halakha, we need to have a more solid, original source for the hekesh.