Gregory the Dialogist

Ver. 30. He shall not depart out of darkness. If this proud man had been minded to turn back from sin to righteousness, he might 'depart out of darkness.' But because he seeks not the light of righteousness, he does not depart out of darkness. After whose example, those likewise, who 'attach themselves to him out breathe themselves in making earthly advancements, are kindled with the torches of avarice, and scorched with the fires of carnal desires. And hence it is added, The flame shall dry up his branches. …

Morals on the Book of Job, Book XII ↗

Thomas Aquinas

To explain this he says, "He will not emerge from the darkness," i.e. from the state of adversity. He gives the reason for not returning to the light when he says, "a flame will dry his branches." For there is still hope of reviving a tree if it has been uprooted as long as its branches remain green because they can be grafted and replanted. But if the branches are burned up, no further hope of reviving it remains. The branches of a man are his sons and other persons related to him in whom a man sometimes rises again from adversity. …

Commentary on Job ↗