Sefer HaBahir 75

1[The students asked,] "And why is 'Tzedek, tzedek [צדק]' (Deuteronomy 16:20) — two times?" [Rabbi Rachumai] said to them, "As is written, 'From the brilliance before Him' (Psalms 18:13). The first 'tzedek' is actual [ממש] Tzedek, and She is Shechinah, as is written, 'Righteousness [צדק] dwells in Her' (Isaiah 1:21)."[They asked,] "And what is the second 'tzedek'?"[He answered,] "This is tzedek that frightens the righteous [צדיקים]." [They asked,] "And is this Tzedek Tzedakah or not?"[He answered,] "No.""Why?""As is written, 'He dons Tzedakah like armor' (Isaiah 59:17) and Tzedek is 'A helm of redemption on His head' (Ibid.). There is no 'His head' other than Truth [אמת], as it is said, 'The head of Your words is Truth' (Psalms 119:160), and there is no Truth other than Peace [שלום], as is said, 'For He will be Peace and Truth in my days' (Isaiah 39:8). Is it possible for a person to say this? Thus, Hezekiah said [that] this trait that You gave to David, my father, is a half day, and peace and truth are half days. Therefore, he mentioned 'my days,' and he mentioned 'peace and truth' and 'in my days', as everything is one, as is written, completeness [שלום] — 'There was evening and there was morning — one day' Genesis 1:5). Just as the day is Peace, so too He seeks peace as is said 'Peace and truth he will be in my days' (Genesis 42:19). With this trait that you gave to David, my father, as is written, 'His throne, as the sun, before him' (Psalms 89:37)."