The two stories both have very similar stories about a great flood, in both stories a person of almighty importance (EA for gilgamesh and God for the bible) tell a man of lower importance (Noah in the bible and Utnapishtim for gilgamesh) to destroy their houses and begin building a boat and to harbour any living creatures aboard to stay safe from the coming flood. however the reasons are different, EA is flooding a city that rejected him, God is flooding the world to clean the sins of mankind. in both instances, they were not allowed to let anyone aboard their ships unless they wished to redeem themselves before the flood happend.