Leviticus is the third book in the Old Testament of the Bible. It is a long, boring list of all the things God doesn't want you to do, There is a long list of punishments, often scourging of stoning to death when people do things that god doesn’t want. And the God who ordained all this is omnibenevolent. Some insects or birds have four legs, and the god who proclaimed all this is omniscient. 
It is the first time out of two in the Bible that God expresses his disdain for shrimp. Luckily for Christians, this list now only applies to those blasphemous Jews, because Jesus said so. It's odd how an omnipotent God can go back on his decisions like that. Also it's just a bit arbitrary, the Ten Commandments from Exodus still apply but rules in Leviticus are accepted or rejected arbitrarily. Usefully for Christians, Leviticus's prohibitions of the things that Christians don't like, such as homosexuality and bestiality, still apply.