Rashi: Their poison. Persians put snake venom on their arrows. Devar Eliyahu - an arrow inflicts three afflictions. (a) The limb that it strikes is torn and withers - "Chitzei Shakai Imadi." (b) If the arrow has venom, it spreads to the entire body. (c) When the enemy shoots arrows constantly, even if they do not strike him, he is terrified, for he remembers the pain from the first. The body feels the wound itself, and the Ru'ach feels the venom ¹ . The Neshamah fears.

Malbim: Elifaz said that his afflictions save him from a greater loss. Iyov refutes this - I cannot recover from this. A cure requires that the illness is not mortal, and the foundations of his body are strong, to stand against the illness. Both of these are lacking. I despise all food - I cannot get strong to overcome this!

Ibn Ezra: This is great fear of Hashem. Devar Eliyahu - it is plural, for the afflictions were in rapid succession.

Ibn Ezra: They wage war with me.

Malbim: Hashem constantly sends against me new arrows.