"If someone sins and commits a trespass against G‑d [in Hebrew, 'vema'ala ma'al b' HaShem'] by lying to his comrade…." (Lev. 5:21-22)

In Kabbalistic terms, every Jewish soul depends on continuous input from celestial forces called "Shefa Neshamot" in order to sustain itself spiritually inside a body. The only soul which does not enjoy this continuous spiritual input is one whose Nefesh (i.e. the person it resides in) has become guilty of criminal sins which will result in its being deprived of the celestial influx mentioned above. This is what the Torah meant when it described the Nefesh being "cut off" in the verse "An uncircumcised male the flesh of whose foreskin shall not be circumcised – that soul shall be cut off his people…" (Gen. 17:14), as the consequence of a Jew ignoring the commandment to circumcise himself or be circumcised.

The celestial spiritual input into our souls…enters by means of two thin threads through a person's two nostrils….

The celestial spiritual input into our souls which we have described enters by means of two thin "threads" through a person's two nostrils, as this is the area where the Nefesh is "joined" to its Owner, to G‑d. This is what Moses meant when he said in the verse: "All of you who have cleaved unto the G‑d your L-rd are alive as of this day." (Deut. 4:4)

If man commits the sins described in this paragraph, his soul comes under the domination of the forces of evil; if the spiritual input from celestial sources were to continue, it would actually strengthen the forces of evil which have taken over in that person. When the Torah speaks of "vema'ala ma'al b'Hashem", this describes such a process of strengthening him who trespassed against G‑d.

…All of Israel are branches of one soul. If any branch of that soul becomes involved in evil, this has repercussions on the entire people. This is the deeper meaning of the words "…by lying [in Hebrew, 'v'kachash'] to his comrade", his denial extends to the members of his people. His people become "kachash", in Hebrew "weak", through his sinful behavior.… The Jewish nation increases in spiritual power by means of its men of valor who contribute to its peace and harmony and who thereby assure it of itself.

[Translated and annotated by Eliyahu Munk]