Adam Clarke on Job 2:6

But save his life - His body thou shalt have permission to afflict, but against his life thou shalt have no power; therefore take care of his life. The original, נפשו שמר naphsho shemor, may be translated, keep his soul; but the word also signifies life; yet in the hands of the destroyer the life of this holy man is placed! How astonishing is the economy of salvation! It is so managed, by the unlimited power and skill of God, that the grand adversary of souls becomes himself, by the order of God, the preserver of that which the evil of his nature incessantly prompts him to destroy!