Musar על נדרים 39:12

A pious man is so called because he has a sense of shame, for the word 'hassid' or 'pious' means 'white', for the translation of 'stork' (Hassidah) in Aramaic is "hawaeita" meaning "the white one", as you note in Leviticus 11:19, and similarly in Isaiah 29:22: "Neither shall his face now become white" (with shame), and the Aramaic translation of "herpah" (shame) is hisda (same as Hassid), as you will note in Genesis 34:14. And all of this for what reason? That the Hassid or pious person must bear shame in order to fulfill the Torah, and he must remove shame from his face at performing any precept. Then he is called a Hassid or "pious one", and thus he attains to prophecy as it is written: "Then didst Thou speak in vision to Thy pious ones" (Ps. 89:20). And through his sense of shame he will attain to true reverence of God, as it is written: "In order that His awe be upon your faces and you do not sin" (Exod. 20:20). What kind of awe or fear of God can be seen in a person's face? You must surely say, "A sense of shame" (which causes the face to change color) (Nedarim 20a).