Yadayim, Chapter Two, Mishnah Four
This long mishnah is about cases of doubtful impurity involving hands. While the mishnah is quite long, it is not actually too difficult.
1) If there was a doubt whether any work has been done with the water or not,
a) A doubt whether the water contains the requisite quantity or not,
b) A doubt whether it is unclean or clean,
c) In these cases the doubt is considered to be clean because they have said in a case of doubt concerning hands as to whether they have become unclean or have conveyed uncleanness or have become clean, they are considered to be clean.
d) Rabbi Yose says: in a case [of doubt as to] whether they have become clean they are considered to be unclean.
2) How so?
a) If his hands were clean and there were two unclean loaves before him and there was a doubt whether he touched them or not;
b) Or if his hands were unclean and there were two clean loaves before him and there was a doubt whether he touched them or not;
c) Or if one of his hands was unclean and the other clean and there were two clean loaves before him and he touched one of them and there was a doubt whether he touched it with the unclean hand or with the clean hand;
d) Or if his hands were clean and there were two loaves before him one of which was unclean and the other clean and he touched one of them and there was a doubt whether he touched the unclean one or the clean one;
e) Or if one of his hands was unclean and the other clean and there were two loaves before him one of which was unclean and the other clean, and he touched both of them, and there is a doubt whether the unclean hand touched the unclean loaf or whether the clean hand touched the clean loaf or whether the clean hand touched the unclean loaf or whether the unclean hand touched the clean loaf
i) The hands remain in the same state as they were before and the loaves remain in the same state as they were before.
Section one: There are three types of “doubts” that could cause the water not to have purified his hands. As we learned in 1:3, if work was done with the water it cannot be used to wash his hands. There must be a quarter of a log (1:1) and the water must be pure.
In all of these cases, if there is a doubt as to whether his hands were purified, the law is lenient and we treat them as pure. Below the mishnah will explain the meaning of “become unclean” and “convey uncleanness.” To become pure means that if he isn’t sure whether he effectively purified his hands, they are considered pure. This refers to the cases in the beginning of the mishnahcases where there was a doubt whether the water he used could purify his hands.
Rabbi Yose disagrees with the ruling concerning doubt over whether his hands have become pure. Because his hands are presumed to be impure, they cannot be considered pure unless we are sure that they have been purified. The status quo remains.
Section two: The mishnah now goes through a long list of cases in which an impure hand might have touched a pure loaf of terumah or vice versa. Note that this is a different type of doubt than in section one. In section one, the doubt was whether his hands had been purified. Here the doubt is whether he defiled a loaf of terumah.
The mishnah rules that in all of these cases his hands and the loaves remain in their previously assumed state. The hand or hands that were pure remain pure and the loaf or loaves that were pure remain pure. In other words, in cases of doubt the status quo remains.