The Great Flood that destroys humans
God look into the earth and sees that the humans that he has created on earth are filled with evil, and he was angry with it , regretting that he has created them, people are getting wicked. They have done many unpleasant things which makes God unhappy.God wanted that all of he had created including the animals , birds and other creatures should be wiped out from Earth.
But sees different from Noah for he is a righteous human , always doing good deeds to his fellow human being. Teaches his sons Shem, Ham and Japeth to fear God and avoid making actions that are against God. God told Noah that he will flood the earth and will wipe all unworthy humans living in it. By that Noah was commanded by God to build an ark that will save him and his family including the pairs of animals of each kind. Noah didn't waste time and obeyed God , he built an ark according to Gods instructions.
He and his sons were criticized by the people during the process of building the ark , but he continue to ignore them and not letting any second to waste. When the time Noah did finish it according to Gods instruction , animals are coming one by one in pairs towards ark.
Noah and his family also go inside the ark , for God has promised to flood this.So they waited inside until a tremendous rains happens filling all the land with waters, time to time waters gone high as they hear outside people cried for help. Noah instructed his sons and their families not open the doors of the ark to help those people. So the great flood happens killing most of the people on earth.
When rain stops and time to time waters gone low, and then land appears. They got off into the ark with the animals , and making some offering to God that they are been chosen to do his command. God made a promised to Noah that he will not flood again the earth , making a sign of a rainbow as a symbol of that promise.
We should obey God and do not do evil that against his commandments , we just continue to do good and God will protect us from harm.