As we learned on yesterday’s daf the eighth perek of Massekhet Shabbat digresses from the central topic of this tractate, turning its attention to the fundamental question: How do we know…?
The Mishna on today’s daf illustrates this type of question-and-answer when it teaches:
From where is it derived that a ship is ritually pure, in the sense that it cannot become impure? As it is stated: “The way of a ship in the midst of the sea” (Mishlei 30:19).
The Gemara explains this teaching as follows:
This verse teaches us by mean of an allusion that the legal status of a boat is like that of the sea. Just as the sea is ritually pure and cannot become impure, so too, a boat is ritually pure and cannot become impure.
The verse in Mishlei states: “There are three things which are too wondrous for me, yea, four which I know not: The way of an eagle in the air, the way of a serpent upon a rock, the way of a ship in the midst of the sea, and the way of a man with a young woman” (Mishlei 30:18–19). If the verse is understood at face value, what is so wondrous about the way of a ship? Therefore, according to some commentaries, the Gemara derives a new halakha from this verse. Even if a ship is made of materials susceptible to ritual impurity, it remains pure, if it is in the midst of the sea. Other commentaries suggest that all of the wonders cited in this verse should be understood along the same lines. A snake causes death, but unlike other creeping animals, it does not transmit impurity when it dies. An eagle is a non-kosher bird but its legal status is like that of a kosher bird, which does not transmit impurity when eaten. The way of a man with a young woman means that a seminal emission is only impure after it has been discharged by the woman, as explained later in this chapter (Me’iri).