Rashi: One who does not repent from his sins and admit to them, he mourns over his assurance to complete the evil that he did all his years. Mischolel is an expression of mourning.

Ibn Ezra: Mischolel is [fear,] like "Chil ka'Yoledah."

Devar Eliyahu: He is like a Chalal ¹ (Mes).

Malbim: Initially Iyov questioned Tzadik v'Ra Lo. He additionally asked about Rasha v'Tov Lo. Elifaz answers, true success is not externally seen success (wealth and pleasures). Rather, it is internal success - if his heart is serene and he rejoices in his portion. Elifaz says that a Rasha lacks this. Even if he seems to succeed, his heart is full of fear like a stormy sea. His heart prophesizes that evils will come upon him.

Divrei Eliyahu: Rasha is evil to Shamayim; Aritz is evil to people.