# Who among you fears Yahweh? Who obeys the voice of his servant? Who walks in deep darkness without light? He should ... his God.

"If someone among you fears Yahweh and obeys the voice of his servant, but he walks in deep darkness without light, then he should ... his God." 

# obeys the voice of his servant

"obeys his servant"

# walks in deep darkness without light

"is suffering and feels helpless"

# trust in the name of Yahweh and lean on his God

"trust in Yahweh, his God"