The germ of the explanation (based on the interpretation in Reshimos HaTzemach Tzedek1 on this verse, and in the above discourse2) is that “Zion” refers to those Jews who occupy themselves in the Torah and its mitzvos. They are called “Zion” because they are distinguished [—“Zion” as in tziun, a “sign”—] in their observance.

{[We find a parallel] in the Jerusalem Talmud which interprets3 the verse:4 “I have placed My words in your mouth and I covered you with the shadow of My hand, planting the heavens, laying the earth’s foundations, and saying to Zion: ‘You are My people,’” as follows:

We have reviewed the entire Scriptures and found that only here are the Jewish people referred to as Zion, (as the verse states), ‘saying to Zion: “You are My people.”5

As is well known, the explanation of the matter is as follows:6 This verse speaks of the “three modes [of service] upon which the world stands: the study of Torah, the service of G‑d, and deeds of kindness.”7 “I have placed My words in your mouth” refers to Torah study; “I covered you in the shadow with My hand” refers to deeds of kindness; “planting the heavens, laying the earth’s foundations” refers to the sacrifices (as stated in the Jerusalem Talmud, ibid.).

This is the meaning of the statement “Only here are the Jew­ish people referred to as Zion.” The Jewish people are [worthy of being] called “Zion” [only] when they occupy themselves in Torah study, the service of G‑d, and the performance of deeds of kindness. For these [three modes of service] represent the Torah and its mitzvos as a whole.}

“Her captives” refers to those who do not occupy themselves in Torah study.8 {The word vishaveha, “her captives,” stems from the root shivyah, 9 “captivity.”} These people are [held] in actual captivity in the body and the animal soul. This is the meaning of “Zion shall be redeemed through justice and her captives through tzedakah.” The redemption of those who occupy them­selves in Torah study comes about through justice; i.e., [their redemption] is an expression of justice. The redemption of the captives, by contrast, comes through tzedakah, [i.e., it is an ex­pression of charity on G‑d’s part].

[This raises a question:] The redemption of the individuals who are held captive by their bodies and their animal souls will come about through teshuvah [repentance], as our Sages say, “Israel shall only be redeemed through repentance,”10 and “The Torah has promised that Jews will eventually repent at the end of their exile and (as a result) they will be immediately redeemed.”11 [This appears to run contrary to the conception that the re­demption will come about as an expression of G‑d’s charity.] Nevertheless, [there is no contradiction]. The fact that repen­tance brings about atonement is in itself, not an act of strict jus­tice, but an expression of G‑d’s charity and generosity.12

{We may say that this is also the connection between the in­terpretation of vishaveha as “her captives” and the explanation that vishaveha refers to those who “turn [to G‑d] in teshuvah. ([The word] vishaveha, also shares a connection to the word teshuvah,13). For the redemption of the captives comes about through their teshuvah.}

[Although the redemption of “her captives” requires tzedakah], it is, nevertheless, on a higher level than the redemption of Zion, [those involved in Torah study]. For the aspect of justice is limited, while the aspect of tzedakah knows no bounds. As explained in the discourse cited previously:14 justice refers to a form of light that is on the level of the vessels [through which it shines], while tzedakah refers to a form of light that is by nature separate and apart, and descends [into our realm] only as an expression of tzedakah. Thus, the light that is drawn down to the righteous individuals whose redemption comes about through justice is [merely] the light that is on the level of the vessels. [And the light granted as tzedakah is much higher.]

{There are two concepts implied by saying that these individuals’ redemption comes about through justice: a) they are not in need of tzedakah, since justice finds them worthy [of redemption]; b) justice negates tzedakah, as it is written,15 “Do not give anyone special consideration when rendering judgment,” and Rashi explains:16 “You should not say this person is poor ... it is a mitzvah to provide him with sustenance.}

The light that is drawn down to those who turn [to G‑d] in teshuvah, and whose redemption is through tzedakah is, by contrast, a light that is by nature [above our material framework and] separate [from it].