פירוש על כלים 19:4

נישא הזב על המטה ועל המיזרן (if the person with gonorrhea was carried on the bed and on the girth) – not exactly carried on the bed girth, but rather that the person with gonorrhea was carried on the bed that the girth is tied around it and extends from it.

If a zav was carried on a bed and on its mattress, the latter causes an uncleanness of two grades and an unfitness of one grade, the words of Rabbi Meir. The zav (person with abnormal genital discharge) causes the mattress to become a primary source of impurity (the bed also is a primary source of impurity, but this mishnah deals only with this mattress). The mattress causes anything that touches it to have first degree impurity. Whatever has first degree impurity imparts second degree impurity to whatever it touches. That which has second degree impurity renders unfit any terumah that it might touch (giving it third degree impurity). But the terumah does not disqualify anything by giving it fourth degree impurity.

מטמא שנים ופוסל אחד דברי ר' מאיר – Rabbi Meir according to his reason that he stated above (see previous Mishnah, Tractate Kelim, Chapter 19, Mishnah 3), that even if the bed birth extends from the bed a little bit, and even more, it is attached/connected to the bed, and the two are made impure and renders [the heave-offering] unit, like the bed itself. For all that the person with gonorrhea is carried upon and acts of lying and sitting are performed by the person with gonorrhea, which is a primary category of ritual impurity, and the person who touches is first degree [level of ritual impurity], and something that is first-degree [level of ritual impurity] makes something else second [degree level of ritual impurity] , and something that is second degree [level of ritual impurity] makes something third [degree level of ritual impurity] to invalidate the heave-offering/priest’s due alone, but not to make it impure. And this is where he defiles two degrees, which are first [degree of ritual impurity] and second [degree of ritual impurity] and he invalidates one and it is third [degree level of impurity] and it is invalid for heave offering alone. And the bed girth all the while that it was not removed from the bed is considered like a primary source of ritual impurity, and it defiles two and invalidates one, but after he removes it, it is nothing other than a derivative of the defilement which defiles one and invalidates one, according to the law of a person who touches that which the person with gonorrhea lies upon.

Rabbi Yose says: if a zav was carried on a bed and on its mattress the part that is shorter than ten handbreadths causes an uncleanness of two grades and an unfitness of one grade, but that which is over the ten handbreadths causes only an uncleanness of one grade and an unfitness of one grade. Rabbi Yose distinguishes between the part of the mattress that extends from the bed less than ten handbreadths and the part that extends more than ten handbreadths. This accords with what he stated in yesterday's mishnah. The part that extends less than ten handbreadths has the same rule that Rabbi Meir stated above. The part that is further away from the bed is treated not like the bed but as if it were a separate piece that had contact with the remainder of the mattress. Therefore, this part has first degree impurity which it got from the main part of the mattress and it defiles that which it touches, giving it second degree impurity. That which has second degree impurity renders unfit any terumah that it might touch (giving it third degree impurity).

ר' יוסי אומר = Rabbi Yossi according to his reasoning, who stated above (in Tractate Kelim, Chapter 19, Mishnah 3) ten handbreadths and not further. Therefore, that which is within ten [handbreadths] is considered a connection/attachment to lying [by a person with gonorrhea], and it defiles two and invalidates one all the while that he did not remove it. But what is beyond ten [handbreadths] is not considered an attachment to the lying [by a person with gonorrhea], and its law is as it was explained, that it defiles one and invalidates one.

If he was carried on the mattress, [on the overhanging part] that was shorter than ten handbreadths, it becomes unclean, but if on the part that was longer than ten handbreadths it remains clean. In this scenario he was carried on the part of the mattress that extends over the bed, but not on the bed itself. If he was carried on the part of the mattress that is less than ten handbreadths from the bed, the mattress is unclean. But if further from the bed, then the mattress is clean because it is not susceptible to "midras" impurity (imparted by sitting, lying or leaning on something) because it is not considered part of the bed. And since the zav did not directly touch the mattress (he touched the mattress covering), the mattress is completely clean.

נישא על המזרן מעשרה ולפנים טמאה – this is our reading (i.e., טמאה). But we don’t have the reading of טמא/impure. And this is an explanation: if the person with gonorrhea was carried on the bed girth that extends from the bed, if he was carried from ten [handbreadths] and within to the side of the bed, the bed is impure through treading/Midras, for since all ten [handbreadths] are considered an attachment to the bed, but from ten [handbreadths] and beyond it is not an attachment/connection to the bed, and the bed is pure and its not defiled [with the defilement] of the bed girth. Such it appears in my eyes an explanation/commentary on this Mishnah. And the reading of my Teachers/Rabbis who have the [textual] reading "טמא וטהור" /impure and pure and their explanation, but it was not acceptable to me. And similarly the words of Maimonides who wrote in his commentary to this Mishnah did not enter my eyes are all. And I investigated afterwards in his work (i.e., the Mishneh Torah) in the Laws of Kelim/Vessels, Chapter 21 [Halakha 9] – it appears to me that there he retracted and explained this Mishnah as I explained it here.