Holy Zohar text. Daily Zohar -86.

Tikkun 3 – continued

Man is a chariot for Zeir Anpin and in the image of the central column.
A man’s prayer need to be in a group of ten people to be able to properly connect Zeir Anpin, which is 6 Sefirot and Malchut to the upper three Sefirot and draw the light.

The male s-e-x organ is in the aspect of Yessod, which is the funnel for the light to come down to Malchut. Those that keep the action of this organ with purity becomes chariot to Yessod and the Holy one protect them from the process of hell.

Explanation: Within the male s-e-x organ embedded the desire to connect to Malchut in order to bring Zeir Anpin, male, and Malchut, female, together. This connection draws the upper light and the force that let us create new in this world.

Since it involve a physical connection then negativity easily attaches to it and transform the desire to draw the light for creation and continuation purpose into a highest degree of desire for the self.
That negativity should be cleanse after death, in the process called hell גיהנם. This in the secret of בראשית letters of ברית אש, meaning fire + Brit (covenant).
The Covenant is the promise of God to Abraham and his descendants to keep the flow of light through Yessod to the world.

(Recommended reading to understand deeper the concept of soul cleansing here: http://rabbishimon.com/?p=89, body and soul part 1 and http://rabbishimon.com/?p=111 for part 2)