Meilah, Chapter 5, Mishnah 5. Throughout this chapter the mishnah has been fixing the sizes and limits that govern me'ilah, the misappropriation of consecrated property. Everything here rests on one rule: a person becomes liable only once the enjoyment he drew from hekdesh reaches the value of a single perutah. The question our mishnah takes up is what to do when that value accumulates piecemeal rather than in one stroke: divided between two people, divided between two different modes of enjoyment, or divided over a span of days.
The Four Combinations
Four pairings appear here. "Achilato va'achilat chaveiro," what he ate and what his fellow ate: he consumed hekdesh valued at half a perutah, and he handed hekdesh of that same value to another person to eat. "Hana'ato vahana'at chaveiro," his enjoyment and his fellow's enjoyment: with consecrated oil, for instance, he smeared half a perutah's value of it on his own skin and an equal amount on his fellow. The mishnah then mixes the categories: "achilato vahana'at chaveiro," what he himself ate together with his fellow's benefit of another sort, and "hana'ato va'achilat chaveiro," his own non-eating benefit together with what his fellow ate.
All four receive a single verdict: "mitztarfin zeh im zeh," each is added to the other. No individual act on its own reached the required measure, and the two portions were not even benefit of one kind (the one taken by mouth, the other by anointing), yet the halves are reckoned together as a full perutah, and the man is liable for me'ilah.
Why They Combine: One Person Behind Both Acts
The reason these separate halves are counted as one is that a single person stands behind all of them. He ate the first half himself, and it was he who placed the second half in his fellow's hand. Both the eating and the benefit came about through his own doing, so the two half-perutahs are not two independent stories; they are one act of misuse of hekdesh that happens to have been distributed between two bodies and two forms of enjoyment.
"Va'afilu Lizman Merubah"
The mishnah continues: "va'afilu lizman merubah," even across a considerable interval. There is no requirement that the two portions occur together. Say that on one day he consumed consecrated food to the value of half a perutah, and only on the day after did he give consecrated food of equal value to his fellow to eat: the two still merge, and liability for me'ilah follows. Elapsed time by itself does not sever one act from the other.
The Real Divider: A Single Lapse of Awareness
Awareness is what severs them. The joining holds only if the entire sequence unfolded inside one period of ignorance, a single stretch during which he never recognized that his conduct was forbidden. Should he have come to know, between the first portion and the second, that what he had done was prohibited, that knowledge splits the sequence in two. He is now left with a pair of distinct incidents, each carrying benefit of merely half a perutah, and neither attains the necessary measure.
Thus a man who acted in ignorance, then learned that his deed had been forbidden, and only afterward took a second half from hekdesh, one half falling before the discovery and one after it, bears no liability for me'ilah whatsoever. The entire perutah of enjoyment has to gather within a single, unbroken period of ignorance.