We may expound neither on [the subject of] illicit relationships to [a group of] three, nor on the account of the Creation to [a group of] two, nor on [the account of] the Merkavah to an individual unless he is wise and understanding through his own knowledge.  Whoever speculates on four things, it would be better for him had he not come into the world: What is above, what is below, what was before, and what will be after.  Similarly, whoever has no regard for the honor of his Maker, it would be better for him had he not come into the world.

Yose ben Yoezer says not to lean [the hands on the head of a sacrificial animal on Yom Tov]; Yose ben Yochanan says to lean. Yehoshua ben Perachiah says not to lean; Nittai the Arbelite says to lean. Yehudah ben Tabbai says not to lean; Shimon ben Shatach says to lean. Shemaiah says to lean; Avtalyon says not to lean. Hillel and Menachem did not disagree. Menachem left [office]; Shammai entered. Shammai says not to lean; Hillel says to lean.  The former [of the respective pairs] were Nesi'im; the latter were heads of the Beis Din.

Beis Shammai say: We may bring shelamim [on Yom Tov] without leaning on them, but [we may] not [bring] olos.  Beis Hillel say: We may bring [both] shelamim and olos, and we may lean on them.

[If] Shavuos falls on the eve of the Sabbath, Beis Shammai say: The day of slaughter is after the Sabbath. Beis Hillel say: There is no day of slaughter after the Sabbath. They concur that if it fell on the Sabbath, the day of slaughter is after the Sabbath.  The Kohen Gadol does not don his [special] garments [on that day]; moreover, they are permitted to eulogize and fast, in order not to confirm the view of those who say that Shavuos is always [the day] after the Sabbath.

We must wash the hands for unsanctified food, for maaser, and for terumah; but for kodesh we must immerse [the hands].  Regarding the [water of] cleansing, if one's hands became contaminated, his [entire] body is [considered] contaminated.

[If] one immersed himself for unsanctified food and [only] intended [to cleanse himself] for unsanctified food, he is prohibited from [eating] maaser. [If] he immersed himself for maaser and [only] intended [to cleanse himself] for maaser, he is prohibited from [eating] terumah. [If] he immersed himself for terumah and [only] intended [to cleanse himself] for terumah, he is prohibited from [eating] kodesh. [If] he immersed himself for kodesh and [only] intended [to cleanse himself] for kodesh, he is prohibited [from touching] water of cleansing.  [If] he immersed himself for a more stringent matter, he is permitted [to occupy himself with] a less stringent matter.  [If] he immersed himself without any intention, [it is deemed] as if he had not immersed himself.

The garments of an am haaretz have midras [-contamination] for perushim. Garments of perushim have midras[-contamination] for those who eat terumah. Garments of those who eat terumah have midras[-contamination] for [those who eat] kodesh. Garments of [those who eat] kodesh have midras[-contamination] for [those who handle] purification water.  Yosef ben Yoezer was the most devout of the Kohanim; yet his napkin was [deemed to have] midras[-contamination] for [those who eat] kodesh.  Yochanan ben Gudgada used to eat according to the purity [regulations] of kodesh all his life; yet his napkin was [deemed to have] midras[-contamination] for [those who handle] purification water.