How will Tzedek be a belt for Masnav?
Rashi citing Targum Yonasan: Tzadikim will be around him, clinging to him like a belt.
Radak: The Tzedek and Emunah in which he will grasp will be strength for him lest his loins slip. The verse repeats the matter in different words.
Malbim: Tzedek and Emunah will not be for him an external acquisition. Rather, like a belt that clings to his loins; it pertains to his body. So they will cling to him and never separate from him - "Ka'asher Yidbak ha'Ezor El Masnei Ish
Why is Emunah called a belt for Chalatzav?
Malbim: Emunah, which is Bein Adam la'Makom, is compared to a belt for his loins that is under his garment. Only the wearer sees it. Emunah hidden in the heart is more than what is seen to the Rabim. This is a Tenai of a true believer; his conscience is more than what is revealed, like Chovos ha'Levavos writes.
