This is a continuation of Part 1.

Rabbi Shimon [bar Yochai] said: Come and see the mystical explanation of these words! Why does the verse use the word year in the singular [form of the word for "year"] after one hundred and after twenty, but "years" [in the plural] after the number seven?1 And [even though each number - one hundred, twenty and seven - will be explained individually] nevertheless [the number one hundred twenty seven] is [also] a single unit.

The higher sefirot…maintain their unity….

The explanation is this: "One hundred year" includes everything, for it constitutes the most concealed sublime place, all as one.2 Sarah is identified with the sefira of malchut (Zohar III, 170b) through which life-force extends to all the worlds. The word for "year" [in Hebrew, shana"] has the same numerical value as the word "sefira" [= 355], thus the verse informs us that the life-force found in malchut [i.e. the term "Sarah's life"] comprises several different layers of sefirot [one hundred years = 100 sefirot; twenty years = 20 sefirot; seven years = 7 sefirot]. One hundred years refers to the sefira of keter3 the most concealed and sublime of the sefirot. Moreover, each of the ten sefirot of keter is comprised of all the other ten (10 x 10 = 100) in a totally unified way (as in the term "includes everything… all as one".) "Year" in the singular alludes to this unity. This is the secret of the one hundred blessings which one should recite each day. [Menachot 43b] According to tradition, the elders of Jerusalem informed King David that one hundred people were dying each day from unknown causes. He decreed that everyone must recite one hundred blessings every day, and the deaths stopped.4 Thus 100 blessings draw down life-force from the 100 sefirot of keter into malchut daily. (Mikdash Melech; Ziv HaZohar; Sulam)

Similarly, "twenty year" [comprising the ten sefirot of chochma and the ten sefirot of bina (Damesek Eliezer; Sulam)] in which the supernal most hidden [keter is clothed]. For this reason "year" is written [in the singular, alluding to the] mystical secret of oneness, for thought [chochma] and yovel[bina5 are never separated.] (See Zohar IIb; II4a)

But seven years alludes to those sefirot - the six sefirot of Zeir Anpin together with the sefira of malchut, the "seven days of Creation" (see Tanya , beginning of Ch. 3) which become separated from what remains supernal and impenetrable. And even though it is all one unity, nevertheless, these divide off into justice and mercy in a number ways. But this does not happen above in the regard to the higher sefirot, which maintain their unity. Accordingly, "seven years" is written in the plural, and not the singular. Nevertheless, all of them are called "living", as the literal translation of the words is read: "these will be the life of Sarah" - i.e. these will always be, for they continue to exist above.

[From Zohar I, p. 121b-122b; translation and commentary by Moshe Miller]