In his Sha’arei Yosher, Rabbi Shimon Shkop argues that the underlying reason for me’ilah is different in kodashei mizbe’ah and in kodashei bedek ha-bayit. In the former, the culpability stems from the fact that he has derived forbidden benefit from a sacrifice that is to be brought on the altar, while in the latter he must pay because he stole an object that belongs to the Temple. Nevertheless, since both are considered kodashei ha-Shem they are viewed as similar enough to be combined. According to Rabbi Hayyim Soloveitchik, however, the obligation to pay is because the object is stolen even in the case of kodashei mizbe’ah. If that is true then the underlying reason for both is identical and we can easily understand why the two can be combined.
As we have learned, the laws of me’ilah – benefitting from consecrated objects in a forbidden manner – are derived from the passage in Sefer Vayikra (5:15-16). Based on those verses, anything that is considered to be kodashei ha-Shem – holy to God – is included, which incorporates objects that have been consecrated for sacrifice in the Temple (kodashei mizbe’ah) as well as those that have been dedicated for general upkeep of the Temple (kodashei bedek ha-bayit). In order for a person to be held liable for me’ilah, he must derive a minimum amount of forbidden benefit – the value of a perutah.
The fourth perek (=chapter) of Massekhet Me’ilah, which begins on today’s daf (=page) deals with such questions as whether these different types of consecrated objects can be combined to reach the value of a perutah for the purposes of me’ilah and the status of a person who derives less that a perutah‘s worth of benefit from a number of different consecrated objects.
The Mishnah on today’s daf teaches that different sacrifices can be joined together for the purposes of determining forbidden benefit to be me’ilah, and that in fact, different types of consecrated objects – kodashei mizbe’ah and kodashei bedek ha-bayit – can be joined, as well. (The Gemara comments that they are separated in the Mishnah only because of other, nonrelated details, which are taught regarding kodashei mizbe’ah.)