Idra Raba: Chapter 25
The skull of Zeir Anpin

Rabbi Shimon explains the process whereby Arich Anpin sent the spark and the fine pure air that spread to create the skull of Zeir Anpin. Thousands of worlds reside in this skull, and dew drips into it from the white head; from that dew which he shakes off his head the dead will be restored to life. Those who awake to everlasting life will merit the white dew, and those who awake to shame and everlasting contempt will merit the dew that has a red hue in it. We read about the illumination of this skull to both sides and how it spreads to His face. When Zeir Anpin observes the face of Arich Anpin and has compassion on the world His face becomes long like that of Arich Anpin. The illumination that spreads from Zeir Anpin to those below requires that those below give dues to Atik Yomin when they are counted in the census.