Why is Jacob a “worm” (Isaiah 41:14)? In his Isaiah: A Covenant to be Kept for the Sake of the Church (Focus on the Bible) , Allan Harman gives a good summary of the standard view: “Israel is called a ‘worm.’ The Hebrew word here ( tole’ah ) is used as a general description of insect larvae and worms. It is the word employed in Psalm 22:6 where the psalmist describes himself as ‘a worm and not a man.’ This verse may well be a conscious allusion to that passage, and now is used of the object of God’s redemptive work. It emphasizes the sense of weakness felt by Israel . . . . [a] description of the poverty and weakness of Israel. In spite of her size and condition she was the only nation that did not need to be afraid” (p. 279).

That seems right. But the other uses of “worm” in the Bible suggest another dimension. Worms are found in Sheol, dining on the dead (Isaiah 14:11). They are linked with the fire of hell that never stops burning (Isaiah 66:24; Mark 9). After Jacob is called a “worm,” the following verses tell Israel that Yahweh is setting them up as a threshing instrument with teeth that will pulverize mountains to chaff (Isaiah 41:15-16; as Yahweh’s Righteousness does earlier in teh chapter, v. 2). Is Jacob a (toothed?) worm also because he devours the dead and turns the wicked into fertilizer?

Worms are most commonly mentioned in the OT in connection with the tabernacle. “Scarlet” translates the same Hebrew word, so-called because worms were the source for dye. Is Jacob also a worm because he is crushed to produce scarlet coloring to glorify the house of God?