Kelim, Chapter Eighteen, Mishnah Four
1) A bed frame that was put on props:
a) Rabbi Meir and Rabbi Judah say it is susceptible to uncleanness.
b) But Rabbi Yose and Rabbi Shimon say that it is clean.
2) Rabbi Yose said: Why is this different from the rectangle frames of the Levites which are clean?
Section one: The rectangle frame was not put into a proper bed but rather propped up so that it stood off the ground. According to Rabbi Meir and Rabbi Judah this setup is enough like a bed that it is susceptible to impurity.
Rabbi Yose and Rabbi Shimon disagree and say that it is clean.
Section two: Here Rabbi Yose argues out his point, by referring to the end of yesterday’s mishnah, where we learned that the rectangle frames used by the Levites are clean. Rabbi Yose says that if those frames are clean since they were not put into a bed, then the frames put on props should also be clean because they too were not put into a bed.