In honor of Lag Ba'Omer, we will bring some excerpts from the Holy Zohar of Rabbi Shimon Bar Yochai. (Tanslations taken from www.jewishsexuality.com)
Zohar, Bereshit 94a
Another began his exposition by referring to the verse, "Unless the L-rd had been my help, my soul would have soon dwelt in (Duma) silence,(Tehillim, 94:17.) We have learned: what is the special merit of Israel that they do not go down to Gehinom, and are not delivered into the hands of Duma (the angel in charge of Gehinom) like the idol worshipping nations? The reason is that they are distinguished by the sign of the Brit.
For we have learned that when a man leaves this world, bands of destroying angels, wielders of fiery judgment, gather to claim him. But when they examine him and see that he bears the sign of the holy Brit upon him, they flee from him, and he is not delivered into the hands of Duma, to be cast down into Gehinom, for whomever falls into his hands is condemned to punishment there. Both upper and lower (angels) are afraid of this sign, and no evil decrees have dominance over a man if he has succeeded in safeguarding this sign, because he is attached to the Name of the Holy One, Blessed Be He.
Zohar, Bereshit 8a
Rav Hamnuna the Elder said this: "Do not let thy mouth cause thy flesh to sin," (Kohelet, 5:5.) A man should not allow his mouth to utter words that may bring him to lustful thoughts, and thus cause his holy flesh, on which is stamped the holy Brit, to sin. For whoever does this is dragged into Gehinom. The one presiding over Gehinom is called Duma, and there are tens of thousands of angels of destruction with him. He stands at the door of Gehinom. But all of those who have guarded the holy covenant of the Brit in this world, he is impotent to harm them.
It is brought down from the Chassidic Masters: "MiBeSaRI" Echeze Elokah - "And from my flesh, I shall see G-d," (Iyov, 19:26.) - The word "MiBeSaRI" is an acronym for "Mi'Toras Rabbi Shimon Bar Yochai" - In other words, from the Torah of Rabbi Shimon Bar Yochai, I shall see G-d.
Zohar Bereshit 94a
Another explained the verse: "And from my flesh, I shall see G-d," (Iyov, 19:26.) What is the meaning of "And from my flesh?" It would be more proper to say, "from my inner essence." However, "my flesh" is to be understood literally (as being the place of the Brit,) as in the verse, "and the holy flesh is removed from thee," (Yirmeyahu, 11:15,) and also, "and my Brit shall be in your flesh," (Bereshit, 17:13.)
For thus we have learned: Whenever a man is stamped with the holy impress of this sign, through it literally he will attain his awareness of G-d, because the holy soul is attached to this place (in the parallel spiritual world of the Yesod.)
But if he does not merit this, because he did not guard this sign, then of him it is written, "They lose the soul of G-d," (Iyov, 4:9,) for he did not properly guard the impress of G-d. If, however, he guards it, then the Shechinah does not part from him….
When is the Shechinah established with him? When he is married, then the sign enters into its intended place….The holy soul is attached to this place, and everything depends on this sign. Thus it is written, "And from my flesh, I shall see G-d." This is the perfection of everything, literally from "my flesh," from this very sign. Therefore, how fortunate are the holy Jewish People who are attached to the Holy One, Blessed Be He; fortunate are they in this world and fortunate in the world to come. Regarding them it is written: "But you who cleave to the L-rd your G-d, are alive every one of you this day," (Devarim, 4:4.)