Ha-mokher et ha-sefina, the fifth perek of Massekhet Bava Batra deals with selling moveable objects. Its opening Mishna continues the questions dealt with in the fourth perek, specifically what is included in the sale of a large object – a ship – that includes many smaller objects within it.
This discussion leads the Gemara to relate a series of stories of ships and sailors, many of them fantastic tales that are difficult to accept literally. The Rashbam’s approach to these stories is that they are told in order to emphasize the magnitude of God’s creations in the world by means of the rewards offered to the righteous as well as explanations of difficult biblical passages, particularly from the Book of Iyyov. Other commentaries feel a need for more specific explanations of the stories, since they include exaggeration beyond reality. The general approach taken by these commentaries is that the stories refer to historical events in the Jewish people’s past.
As an example, the Gemara tells of an incident related by Rabba bar bar Ḥana, who says that he saw a giant frog that was swallowed by a serpent, which was then eaten by a raven. The raven sat on a tree, which successfully supported the raven’s weight. Rabba bar bar Ḥana concludes by commenting on the strength of the tree that could hold up such a bird, and Rav Pappa bar Shmuel says that had he not seen this with his own eyes, he would not have believed it.
The Ritva and Maharsha approach this story as a metaphor for various kingdoms that rise and rule, but then are destroyed by others. The great strength of the tree, representing God (or, according to the Maharsha, the merit of Avraham Avinu), is nevertheless successful in keeping the Jewish people alive throughout this turmoil – which is what Rav Pappa bar Shmuel attests to.
Other explanations are offered by the Gr”a, who sees the frog as representing Torah scholars and the serpent as representing the evil inclination that tries to keep the scholar from learning by obligating him in daily concerns with earning a livelihood and so forth. The Maharal suggests that the various animals represent natural forces competing for supremacy in the world, all of whom are supported by the great tree of life, that is, by God.