This entry originally appeared on our online encyclopedia, InnerPedia.org here: http://www.innerpedia.org/index.php?title=Ehevi
Ehevi is a group of four Hebrew letters: alef, hei, vav, yud, which, in addition to serving as consonants, constitute the four vowel-letters of the Hebrew Alphabet. They are thus the spiritual dimension or "soul" of the alef-beit.
All of the essential Names of God (Havayah, Kah, Ekyeh, and the hidden Name Akvah) are constructed solely of these letters. In the order of the alef-beit, this group of letters is perfectly symmetric from 1 to 10 (alluding to the inner presence of the 10 sefirot within the 22 letters of the alef-beit): alef =1; hei = 5; vav = 6; yud = 10. In addition, they combine to equal 22 (thereby implying that in essence they contain within themselves the source of all the 22 powers inherent in the 22 letters of the alef-beit).
Often, Ehevi in considered itself to be a Divine Name, a companion Name to Akvah. Akvah represents the "right side" of da'at, the origin of the male principle inherent within da'at, where as Ehevi corresponds to the "left side" of da'at, the origin of the female principle inherent within da'at.
Together, the two Names = 39 (17 plus 22 = 39), the identical value of Havayah Echad ("Havayah is one"; 26 plus 13 = 39). (The Name Akvah first appears in the Torah as the initial letters of the four words beginning with the fourth word of the Torah, "the heavens and the earth." The ordinal values of these four words from the beginning of the Torah are 4, 5, 6, 7, which combine to = 22, the value of Akvah's companion Name Ehevi. In addition, the initial letters of all the 7 words of the first verse of Creation = 22).
When the two Names are multiplied letter by letter the total value = 112 (1 times 1 = 1; 5 times 5 = 25; 6 times 6 = 36; 5 times 10 = 50; 1 plus 25 plus 36 plus 50 = 112). This is the value of Havayah Elokim (1 plus 25 = 26 = Havayah ; 36 plus 50 = 86 = Elokim [the first three of Elokim = 36; the last two letters of Elokim = 50]), the "full Name" of God (wherein His attribute of mercy—Havayah—precedes and "sweetens" His attribute of strict judgment—Elokim. This union and "sweetening" process is a function of the power of da'at, the union of the two hidden Names of God, the two "sides" of da'at, Akvah and Ehevi).
In at-bash, Ehevi transforms to tav, tzadik, pei, mem, which = 610. As Ehevi corresponds to the left side of da'at, the origin of gevurah in da'at, it is understood to relate to the Name Elokim (the Name of gevurah). Elokim in at-bash = 560. 610 plus 560 = 1170 = 26 times 45. 26 = Havayah ; 45 = the primary "full spelling" of Havayah, which = adam, "man." The revelation of the absolute union of God and man is thus seen to derive from the power of the "left," the power to concentrate and capsulate the infinite within the confines and well-defined form of the finite.
The 4 primary "full spellings" of Ehevi (which correspond of those of Havayah and Akvah), 150, 153, 159, 168, combine with those of its companion Name Akvah (136, 143, 154, 163) to = 1226 = 2 times 613. Thus we see that the two sides of da'at are in fact two perspectives, or states of consciousness, with regard to the totality of the 613 commandments (connective forces of man to God) of the Torah, the power to connect to God through love and the power to connect to God through awe.