20And in the twenty-eighth jubilee Noah began to enjoin upon his sons' sons the ordinances and commandments, and all the judgments that he knew, and he exhorted his sons to observe righteousness, and to cover the shame of their flesh, and to bless their Creator, and honour father and mother, and love their neighbour, and guard their souls from fornication and uncleanness and all iniquity.21For owing to these three things came the flood upon the earth, namely, owing to the fornication wherein the Watchers against the law of their ordinances went a whoring after the daughters of men, and took themselves wives of all which they chose: and they made the beginning of uncleanness.
22 And they begat sons the Naphidim, and they were all unlike, and they devoured one another: and the Giants slew the Naphil, and the Naphil slew the Eljo, and the Eljo mankind, and one man another.
23 And every one sold himself to work iniquity and to shed much blood, and the earth was filled with iniquity.
24 And after this they sinned against the beasts and birds, and all that moves and walks on the earth: and much blood was shed on the earth, and every imagination and desire of men imagined vanity and evil continually.
25 And the Lord destroyed everything from off the face of the earth; because of the wickedness of their deeds, and because of the blood which they had shed in the midst of the earth He destroyed everything.
Date: 150-100 B.C.E. (based on scholarly estimates)
Genesis Rabbah 33:5
AND IT CAME TO PASS AT THE END OF FORTY DAYS, THAT NOAH OPENED THE HALON [WINDOW] OF THE ARK. This supports the view that it was a window [trapdoor]. 3 AND HE SENT FORTH A RAVEN (VIII, 7): thus it is written, He sent darkness, and it was dark (Ps. cv, 28). AND IT WENT FORTH TO AND FRO (YAZO WASHOB). R. Judan said in the name of R. Judah b. R. Simon: It began arguing with him: 'Of all the birds that thou hast here thou sendest none but me!' 'What need then has the world of thee?' he retorted; 'for food? for a sacrifice?' R. Berekiah said in R. Abba's name: The Holy One, blessed be He, said to him [Noah]: 'Take it back, because the world will need it in the future. 'When?' he asked. 'When the waters dry off from off the earth. He replied: 'A righteous man will arise and dry up the world, and I will cause him to have need of them [the ravens],' as it is written, And the ravens ('orbim) brought him bread and flesh, etc. (I Kings xvn, 6). R. Judah said: It refers to a town within the borders of Bashan called Arbo. R. Nehemiah said: Ravens literally are meant, and whence did they bring him [food]? From Jehoshaphat's table. R. Akiba preached in Ginzak on the theme of the Flood, and the audience did not weep, but when he mentioned the story of the raven they wept. He then quoted this verse: The womb (rehem) forgetteth him; the worm feedeth sweetly on him; he shall be no more remembered; and unrighteousness is broken as a tree (Job xxiv, 20). 'Rehem forgetteth': They [the generation of the Flood] forgot to be merciful to their fellow men, therefore the Holy One, blessed be He, made His mercy forget them. 'The worm feedeth sweetly on him': the worm became sweet through [feeding on] them, 'He shall be no more remembered, and unrighteousness is broken as a tree': R. Aibu said: It is not written, 'is uprooted' but 'is broken': i.e. like something which is broken, yet produces another stock in exchange; and to what does that allude? To the generation of the Separation [of races].