Cassuto's commentary, he mentions many descriptions and interpretations of certain verses and messages within chapter 7 of the book of Genesis. Through his commentary, U. Cassuto explains many of his points making the story more interesting and fascinating to the reader.
In chapter seven of the book of Genesis, Noah is told by God to bring seven pairs of every clean animal along with him in his ark. It is not explained by God why these animals are needed. As U. Cassuto explains, these animals are to be used for sacrificial purposes and to re-populate the barren earth after the flood. "For the time being the purpose was not revealed to him once more the righteous man, who obeys God's commandment is put to the test The intention is not to command Noah to bring sacrifices, but to make it possible for him to do so" (Cassuto, 73). With this, Cassuto explains why Noah was not given a reason for bringing more than one pair of clean animals, for he had to figure it out himself. Because Noah is seen as a righteous man, he was able to understand and please God by using the clean animals for the intended reasons.
In regards to the command to bring seven pairs of birds of the air, God never distinguished to Noah the need for clean or unclean birds. He simply stated to bring seven pairs of birds because, as U. Cassuto illustrated, Noah needed to make use of both types (Cassuto, 76). As stated in the previous paragraph the clean birds were needed for sacrifices and the unclean (such as a raven) were needed to send forth from the ark to survey the earth. When this command was given, however, Noah was left unaware of what kind of birds would be needed. As U. Cassuto points out, Noah was forced to bring both categories because "if an accident befell one of them that entire species would be destroyed" (Cassuto, 76).
Cassuto also illustrates the importance of the number seven in chapter seven of the book of Genesis.