JE is a hypothetical intermediate source text of the Torah postulated by the DH. It is a combination and redaction of the Jahwist (J) and Elohist (E) source texts. According to this hypothesis, J was composed c. 950 BC, E was composed c. 850 BC, and the two were combined into JE c. 750 BC. JE was combined into the Torah c. 400 BC.
Nature of the JE source
JE treats God as a human-like figure, capable of regret, and appearing in person at events. JE makes use of supernatural creatures such as angels as intermediaries, as well as mystical talking creatures, and supernatural objects to display purity and evil combined. In JE, God is shown as merciful and capable of being persuaded to change his mind.
The Redactor of JE
JE was created when J and E were combined and edited together. The DH asserts that this occurred during the Babylonian exile, involving Ezra, with the encouragement of Cyrus the Great, who was interested in unifying the Jewish exiles by redacting the holy texts.
Since the majority of each text was composed of traditions about events and people associated only with one or other nation, combining them would not cause conflict. However, where they differ, (for example one refers to the holy mountain as Sinai, and the other as Horeb), because of the presence in a general audience of both groups, neither text could be suppressed, and the differences had to be kept in order that the resulting text was generally acceptable.
It is considered unknown how much of the two texts was cut to produce JE. J is the only source used in JE for the stories of the creation, flood, and genealogies. E starts abruptly with the appearance of Abraham and Sarah in Genesis 20, which makes it appear that some of it was left out.
The Redactor of JE is believed to have added very little to the two sources. Only a few phrases to remove serious contradictions and continue the flow of the story in Genesis and Exodus appear to be from the JE redactor. The primary exception is the story of Abraham binding Isaac for sacrifice in Genesis 22 (from E), where the JE redactor is believed to have added an angel stopping Abraham from sacrificing Isaac and replacing the boy with a ram. If this is the case, the original E source had Abraham carry through with the sacrifice of Isaac.
Richard Elliott Friedman, The Bible with Sources Revealed. Harper San Francisco, 2003.