Genesis is the first of the 66 books that compose the Bible and it has as central theme the revelation of the previous God and creator of all things, the man's creation (Adam) and of the woman (Eva), the original sin, the human reproduction and a perverted humanity formation for the sin and the concern of God in rescuing the man of his sinful condition. An important event, the Flood, divides the book in two parts which can be called periods before and after Flood. In the before period the book reveals the previous God and the work of the creation, heavens and earth and everything that there are in them and it highlights the divine zeal for all created things. It treats in peculiar of the man and woman's creation, done to the image and likeness of God, demonstrating the intimacy of God with the man and the importance of this one in relation to the other creatures. It speaks about the garden of Éden, wonderful place where, at the beginning, the man and the woman lived and they enjoyed complete happiness, in communion and intimacy with God. The original sin and its consequences, when the man, tried by the serpent, disobeyed God and ate of the fruit of the tree of the knowledge of good and evil and because of that he was moved away from the God's presence and expel from the Éden. The human reproduction on the earth, and a sinful humanity formation, worthy even of being destroyed by the flood. The mercy of God, who saw in Noah seed of justice and preserved him, him and his family and more the animals of the Ark, from the destruction of the flood. And the own flood that rained on the earth during 40 days burying every flash that was out of the ark built by Noah. It is standing out in that period the human being longevity, there, people lived on average more than 800 years, and they seemed to be very endowed, in general capable of great facts. In the after period the book treats of Noah's establishment and his family in a washed earth, and the begin of a new humanity, which therefore soon would give signs of still being under the domain of the sin, symbolized, mainly, in the episodes of the Tower of Babel, that led off the several languages and in the destruction of Sodom and Gomorrah, for the fire and sulfur, two cities whose inhabitants reached level of corruption similar to that of before the flood.
The focus of Genesis now is on the action of God preparing the bases of the people of Israel. As well as before the flood, God saw seed of justice in Noah, now He sees it in Abraham and separates him to form a new nation that he is the first patriarch. Abraham's woman, Sara, was sterile and both already advanced in age, then a question didn't silence: How to form a new nation without descent? It is here that enters the divine action, converting them fertile and as indicating that the history of that new people would depend a lot on the miracles of God. Abraham bigot Isaac, who bigot Jacob, who passed to be called Israel, that wants to say People of God. It is standing out in this period, the alliance that God made with the humanity, not promising more to destroy it by flood, giving the rainbow as sign of that. Also the angels' presence in some episodes in direct contact with humans. The permanent blessing on Abraham and his descendant. Abraham almost sacrificed in holocaust the son of the promise, Isaac. The troubles of Jacob and his fight with his twin brother, Esau. The birth of Jacob's 12 children, who became the 12 tribes of Israel and the brother Joseph's sale as slave to Egypt. Due to a great hunger the people of Israel went to Egypt in order to feed (because José, before slave, now became governor in the land). The book of Genesis finishes with the death of Jacob and later the one of Joseph and the people of Israel already becoming slave in Egypt. Let me the reader the following inference: Genesis reveals that there is only one God, creator of all the things. There is a humanity submitted by the sin, which needs the divine help. God wants to help the man and to rescue him from the sin, and He chose Israel to accomplish his plan.