According to Sefer Yetzirah, each month of the Jewish year has a letter of the Hebrew alphabet, a zodiac sign, one of the twelve tribes of Israel, a sense, and a controlling limb of the body that correspond to it.
Tishrei (in Hebrew: תִּשְׁרֵי) is the seventh of the twelve months of the Jewish calendar.
The month of Tishrei begins the period (tekufah) of the autumn, which comprises the three months of Tishrei, Cheshvan, and Kislev. The three tribes corresponding to the months of Autumn are Ephraim, Menashe, Benjamin--who in the desert encampment around the tabernacle were situated to the west. Their joint camp was known as the camp of Ephraim.
In the Bible, Tishrei is called "the month of the strong" or "the month of the ancients" (Yerach Ha'eitanim). With respect to the reckoning of "years," Tishrei is the first month of the year (before the giving of the Torah to Israel, Tishrei was the universal first month of the year).
The letters of Tishrei in Hebrew (תשרי) permute to spell the word "beginning" (רשית) as it appears in Deuteronomy 11:12, a verse describing Divine Providence over the Land of Israel and the entire world: "Always are the eyes of Havayah your God there, from the beginning of the year until the end of the year."
As the seventh month from Nissan (the month of Jewish redemption and independence), Tishrei is the "dearest" of months, as the sages say, "All sevens are endeared." In Hebrew, the word "seven" (שבע) is spelled the same as and is cognate to the word for "satiated," and so the month of Tishrei is referred to as "the most satiated of months," for more than any other month of the year it is full of mitzvot and holidays.
Tishrei also begins the six months of the winter, which the Arizal explains correspond to six levels of "reflected light" (in Divine service reflected light corresponds to arousal from below). This is alluded to in the name Tishrei, which begins with the three letters tav shin reish (תשר), in the reverse, or reflected order of the alef-beit (i.e., from end to beginning).
Lamed is the only letter of the Hebrew alphabet whose shape ascends above the upper boundary of the letters. This is understood to reflect the great existential longing and aspiration of the lamed to return to its ultimate and absolute source in the essence of God's Infinite Being. This suggests the experience of true teshuvah ("return to God") during the High Holidays, Rosh HaShanah and Yom Kippur.
On Sukot, we pray with the Four Species, the centerpiece of which is the lulav, a closed date-palm branch. In Hebrew, the word lulav (לולב) is written with two lamed's suggesting that God's infinite light descends and becomes manifest in the two lameds of the lulav on the festival of Sukot.
Libra, the scales, symbolize the Divine judgment of Rosh HaShanah and Yom Kippur. During these days, all of the deeds of man are weighed in judgment.
The Hebrew word for Libra is moznayim (מאזנים), which stems from the word for "ears" (אזנים). Thus, Tishrei's mazal, libra, implies equilibrium and balance (the inner sense of the ears). In Kabbalah, equilibrium is the prerequisite state for marital union, described as a face-to-face relationship. This is the spiritual state that can be achieved on the month of Tishrei in our relationship with the Almighty.
Drawing the 12 months of the year on a circle, Tishrei lies directly across from Nissan and thus the two months face one another. Tishrei receives and integrates into nature (and its fixed laws) the redemption of Israel (the light of Nissan). Due to this itself, God judges Israel on Tishrei with mercy.
Efraim is the son of Joseph, the archetypal soul of the power to procreate in marital union. The name Efraim derives from God's first commandment to Adam on the day of his creation--the first of Tishrei, Rosh HaShanah, "be fruitful and multiply," the all-inclusive mitzvah to procreate.
As explained in the writings of the Arizal, spiritually, this mitzvah is performed on a universal level in ongoing stages throughout all the holidays of Tishrei, from Rosh HaShanah to Shemini Atzeret and Simchat Torah culminating with the birth of new souls, or new Divine consciousness on the seventh day of Passover.
This universal spiritual communion is alluded to in the verses: "His left hand is under my head, and His right hand embraces me" and "He shall kiss me with the kisses of His mouth." More specifically:
In Hebrew, the word for "touch" (משמוש) is cognate to the word for "marital relations" (שימוש). This is the sense which directly relates to the name Efraim, as explained above.
The sense of touch is the only one of the five senses which is not centered in the face (but rather in the tips of our fingers). The procreative "touch" takes place in an existentially and emotionally balanced state of a face-to-face relationship between husband and wife, but in the dark (with modesty, tzniut), for its ultimate source is in the unknowable head of the sefirah of crown (keter).
Green humor resides in the gall. It is the source of all sexual arousal, as taught in Kabbalah.
Green humor represents the well-balanced or blended state (in Hebrew, the words for "blended" [מיזוג] and "marital communion" [זיווג] are cognate) between the white humor (which resides in the lungs) and the red humor (which resides in the liver). Similarly, the month of Tishrei, the beginning of the autumn, blends summer and winter. And so are we taught, that the procreative "touch" (of Tishrei) functions best when performed during the time of the day that is balanced between hot and cold, i.e., at or immediately after "midnight," between the two halves of the night.
Through the intense spiritual service of Tishrei the green humor of the gall becomes rectified and well-balanced in order to control and permeate all of man's activities (throughout the coming year) with Divine procreative energy.