Yakhin ("establish") corresponding to Netzach ("eternity, victory by winning").
Boaz ("strength") corresponding to Hod ("glory, submission, strength by acquiescing").
These are the two "legs," because they are the literal pillars of the Temple physically, and spiritually they're the "legs" of Zeir Anpin.
Tikunei Zohar Intro, 12b bottom
This house has three roofs, and they are the three pillars that support it and they
are ו' ו' ו ' which it says about them, “the vavei hooks of the pillars and their bands of
silver” (Exo. 27:10). Three pillars, these are the three fathers, which support the house
which is the Shechinah. “and their bands” these are the two pillars of truth (Netzach and Hod). Which it
says about them, “Yachin, and Boaz”, and upon them the house stands. And the
“middle beam” (Exo. 26:28), this is the point within, which is concealed within. "the
beam" this is the ו' . Which is the drawing down (Page 13A) of that point which is the
letter י' which certainly extends. "From the end” this is the upper ה' “to the other end”
this is the lower ה'. The tying of the three pillars which are the vavei hooks of the pillars,
is eighteen worlds. Three ו' ו' ו ' equal the gematria of (18) חי (life), which is the
“tzadik foundation of the world”. ה' ה ' when taken from the middle pillar which is
called the "middle beam" they are called beams on account of it, as it is written, “five
beams for the boards of the side of the Mishkan” (Exo. 26:27).
וביתא דא אית ליה תלת גגין, ואינון תלת עמודין דסמכין לה, ואינון ו'ו'ו', עלייהו אתמר ווי העמודים וחשוקיהם כסף, תלת עמודים אלין תלת אבהן, דסמכין לביתא דאיהי שכינתא, וחשוקיהם אלין תרין סמכי קשוט, דאתמר בהון יכין ובועז, ועלייהו ביתא קיימא, והבריח התיכון דא נקודה מלגאו, דסתים מלגאו, מבריח דא ו', אתפשטותא:
Zohar Achrei Mot III:58a
We have learned that this river gave forth deep streams, WHICH
REPRESENT THE THREE SFIROT - CHESED, GVURAH AND TIFERET
OF ZEIR ANPIN - with the anointing oil to replenish the Garden of
Eden, WHICH IS MALCHUT, and water the trees and plants, NAMELY
THE SFIROT OF MALCHUT. Of this, it is written, "The trees of
Hashem have their fill; the cedars of Lebanon, which He has
planted" (Tehilim 104:16). These streams, NAMELY CHESED,
GVURAH AND TIFERET, flow and continue on and join two pillars
that the Baraithas refer to as Yachin and Boaz, NAMELY NETZACH
AND HOD. These NAMES are appropriate. From there, NETZACH
AND HOD come out all these streams, NAMELY CHESED, GVURAH
AND TIFERET, and rest in a certain level referred to as Righteous,
NAMELY YESOD, as is written, "But the righteous is an everlasting
foundation (Heb. yesod)" (Mishlei 10:25). All together they join in
that level referred to as "sea" that is the sea of wisdom, NAMELY
MALCHUT. This is the meaning of the verse, "All the rivers run into
the sea" (Kohelet 1:7).
ותאנא, ההוא נהר אפיק נחלין עמיקין, במשח רבות, לאשקאה גנתא, ולרוואה אילנין ונטיעין, דכתיב (תהלים קד טז) ישבעו עצי יהו"ה ארזי לבנון אשר נטע, ואינון נחלין נגדין ואתמשכן ומתכנשין בתרין קיימין (נ"א סמכין), ואינון ברייתי, (תרי) קרינן להו (מ"א ז כא) יכי"ן ובוע"ז, ושפיר. ומתמן נפקין כל אינון נחלין, ושריין לון בחד דרגא דאקרי צדיק, דכתיב (משלי י כה) וצדיק יסוד עולם, וכלהו אזלין ומתכנשין לההוא אתר דאקרי ים, והוא ימא דחכמתא, הדא הוא דכתיב, (קהלת א ז) כל הנחלים הולכים אל הים וגו'.
Zohar Emor III:90b
"seal the Torah" refers to the sealing of the Torah, the Written
Torah, WHICH IS ZEIR ANPIN. Where does this happen? "among My
disciples," the prophets CALLED "TAUGHT OF HASHEM," NETZACH
AND HOD, as written, "And he set up the right pillar, and called its
name Jachin," WHICH IS NETZACH, "and he set up the left pillar, and
called its name Boaz" (I Melachim 7:21), WHICH IS HOD. From there
ways extend to the faithful prophets, WHO RECEIVE FROM
NETZACH AND HOD, and these support the body, ZEIR ANPIN with
HIS six lights. This is the meaning of, "His legs are pillars of
marble" (Shir Hashirim 5:15). HIS LEGS, THE SECRET OF NETZACH
AND HOD, ARE PILLARS OF ZEIR ANPIN THAT HAS SIX SFIROT IN
HIM. Everything is supported only by MEANS OF perfection, and all
their holiness dwells on them only when they are in holiness. For
when ZEIR ANPIN AND MALCHUT are united with each other, all is
whole, all is one, and no place is rendered defective. Hence the
Congregation of Yisrael is called whole, as written, "And
Melchizedek king of Shalem (lit. 'whole')" (Beresheet 14:18), AS
MELCHIZEDEK IS MALCHUT AND THE KING OF WHOLENESS. AND
ALSO, "In Shalem also is His tabernacle" Tehilim 76:3), WHICH
REFERS TO MALCHUT.
בלמודי אלין נביאי כד"א ויקם את העמוד הימני ויקרא שמו יכין ויקם את העמוד השמאלי ויקרא שמו בועז ומתמן אתפרשן אורחין לנביאי מהימני וקיימי אלין בקיומא לגופא לשית טהירין הה"ד שוקיו עמודי שש. וכלא לא קיימא אלא בשלימו ולא שרייא קדוש' דכלא אלא בשלימו כד מתחבראן דא בדא כלא הוא שלים כלא הוא חד לא אתפגי' אתר. וע"ד אקרי כ"י שלם כד"א ומלכי צדק מלך שלם ויהי בשלם סכו. ובג"כ לא שרייא כלא אלא באתר שלים ועל דא כל איש אשר בו מום לא יקרב כגוונא דא קרבנא דביה מומא לא יתקריב מאי טעמא דכתיב כי לא לרצון יהיה לכם.