[If] a Gentile lent [money] to a Jew on his chametz, [then] after Pesach [deriving] benefit from it is permitted. But [if] a Jew lent [money] to a Gentile on his chametz, [then] after Pesach [deriving] benefit from it is forbidden.  [If] a ruin collapsed over chametz, it is regarded as removed. Rabban Gamliel says: Provided a dog cannot search it out.