Something went terribly wrong in the early days of the world. According to the Book of Jubilees, a group of ancient texts dated to approximately 160-150 BCE, the children of men multiplied across the face of the earth, and daughters were born to them in great numbers. The angels in heaven looked down and saw that the daughters of men were beautiful beyond measure.
These were not ordinary angels. The Watchers, as they were called, had been stationed in heaven to observe and guide humanity. Their task was sacred, their position exalted. Yet desire overtook duty. One by one, these celestial beings began to lust after mortal women, and they made a fateful decision: they would descend from heaven, take human wives, and father children with them.
The offspring of these unions were no ordinary children. They grew into the Nephilim (נפילים), giants of terrifying strength and insatiable appetite. These hybrid beings consumed everything humanity produced, and when that was not enough, they turned against the people themselves. Violence spread across the earth like a plague.
God watched as the corruption deepened. The very beings He had appointed as guardians had become the source of humanity's ruin. The Watchers had introduced forbidden knowledge to the world — the arts of warfare, sorcery, and seduction — and the earth cried out under the weight of bloodshed and sin.
This passage from Jubilees 5:1 sets the stage for one of the most dramatic episodes in Jewish apocalyptic literature: the great flood that would wipe the slate clean. The corruption had become so total that only complete destruction could restore the world to its intended purpose.