The epithet employed to designate the character of God's people

(William Nicholson, "Fears Dispelled!" 1862)

"Do not be afraid, O worm Jacob" Isaiah 41:14

The epithet employed to designate the character of God's people
is "worm." This word is used to describe a base, weak, vile, and despised thing, "How much less man, who is but a maggot — a son of man, who is only a worm!" Job 25:6

(1.) This epithet implies baseness.
A worm is a creature of little worth;
its residence is the ground;
it has no beauty in it.
What is more contemptible than a worm?

Just so, man's origin as to his body, is the dust. In his fallen state, he is empty, having no good in him — and lighter than vanity. Sin has . . .
  degraded him,
  enervated his powers, and
  alienated his heart from God.

This baseness is frequently felt by Christians . . .
  when they think of the grandeur and glory of God,
  when they think of their sins and imperfections,
  when they think of their duties and trials, their ignorance, and their tendency to return to the dust from whence they came.

(2.) This epithet implies pollution. A worm is regarded as unclean. Its element is putrescence.

Just so, man is now degraded from his original dignity even below the brute creation! Yes, he has debased himself even unto Hell! "Ah, sinful nation, a people loaded with guilt, a brood of evildoers, children given to corruption! They have forsaken the LORD; they have spurned the Holy One of Israel and turned their backs on him. Your whole head is injured, your whole heart afflicted. From the sole of your foot to the top of your head there is no soundness — only wounds and welts and open sores, not cleansed or bandaged or soothed with oil!" Isaiah 1:4-6

Every Christian feels his tendency to pollution — he feels himself to be a worm.

(3.) This epithet implies danger. A worm is a creature frequently exposed to danger. Every foot is ready to crush it.

Just so, the body of man is liable to casualties — to death, sudden or protracted, from insignificant causes. And the precious soul of man is surrounded by danger — sin, the world, sinful pleasures, and Satan, are ready to crush it!

(4.) This epithet implies weakness. A worm is not able to make resistance, defend itself, or attack its opponent.

Just so, what resistance can a rebel sinner make against God! Ah! he is only a worm. "Woe to him who quarrels with his Maker, to him who is but a potsherd among the potsherds on the ground!" Isaiah 45:9

What can a believer do against his enemies — the world, the flesh, and the devil — without Divine aid? Without it, he feels himself to be a worm.

"Do not be afraid, O worm Jacob, O little Israel — for I Myself will help you, declares the LORD, your Redeemer, the Holy One of Israel!" Isaiah 41:14