The evening of the fourteenth [of Nissan] we must search for the chametz by the light of a candle. Any place into which chametz is not brought does not require a search.  So why have the Sages said, “Two rows of a [wine] cellar [must be searched]?” [The Sages were referring to] a place into which chametz. is brought.  Beis Shammai say: Two rows over the entire front of the [wine] cellar [must be searched]; but Beis Hillel say: The two outer rows which are the uppermost.

We need not be concerned that a weasel may have dragged [chametz] from house to house or from place to place, for if so, [then we would have to be concerned] from courtyard to courtyard and from town to town, and there would be no end to the matter.