This is a metaphor for a person's work being shown to have no value. This can be stated in active form. Alternate translation: "if the fire destroys anyone's work" or "if the judgement shows that a person's work has no value" (See: [[rc://en/ta/man/jit/figs-metaphor]] and [[rc://en/ta/man/jit/figs-activepassive]])
The abstract noun "loss" can be expressed with the verb "lose." Alternate translation: "he will lose his reward" (See: [[rc://en/ta/man/jit/figs-abstractnouns]])
This can be stated in active form. Alternate translation: "but God will save him as though through fire" (See: [[rc://en/ta/man/jit/figs-activepassive]])