Biblical mystery

Lilith

Adam's first wife?
Lilith is believed to have originated as a female Mesopotamian storm demon associated with wind and was thought to be a bearer of disease, illness, and death. The figure of Lilith first appeared in a class of wind and storm demons or spirits as Lilitu, in Sumer, circa 4000 BC. The phonetic name Lilith is traditionally thought to have originated in Ancient Israel, and to have pre-dated at least 700 BC.
In Jewish folklore, Lilith is the name of Adam's first wife, who was created at the same time and from the same earth as Adam. She left Adam after she refused to become subservient to Adam and then would not return to the Garden of Eden after she mated with archangel Samael. Her story was greatly developed, during the Middle Ages, in the tradition of Aggadic midrashim, the Zohar and Jewish mysticism. The resulting Lilith legend is still commonly used as source material in modern culture, literature, occultism, fantasy and horror.

Cain and Abel

Motives of the murder
Though Genesis depicts Cain's motive in killing Abel as simply being one of jealousy concerning God's favor for Abel, this is not the view of many extra-biblical works. The Midrash and the Conflict of Adam and Eve with Satan both record that the real motive involved the desire of women. According to Midrashic tradition, Cain and Abel each had twin sisters, whom they were to marry. The Midrash records that Abel's promised wife was the more beautiful. Cain would not consent to this arrangement. Adam proposed to refer the question to God by means of a sacrifice. God rejected Cain's sacrifice, signifying His disapproval of his marriage with Aclima, and Cain slew his brother in a fit of jealousy.
In The Church of Jesus Christ of Latter-day Saints and the Community of Christ, there is a different view, found in part of their scripture, the Book of Moses (part of the Joseph Smith Translation of the Bible), which describes that Cain's motive is still jealousy, jealous of God's acceptance of Abel's offering and also Abel's livestock of which he is jealous. This translation also holds that it was Satan that "commanded" Cain to make the offering, thus making Cain's sacrifice vain and faithless.

Image source: commons.wikimedia.org