Book of Thel 4

III.

Then Thel astonish'd view'd the Worm upon its dewy bed.

Art thou a Worm? image of weakness. art thou but a Worm?
I see thee like an infant wrapped in the Lillys leaf;
Ah weep not little voice, thou can'st not speak, but thou can'st weep:
Is this a Worm? I see they lay helpless & naked: weeping
And none to answer, none to cherish thee with mothers smiles.

The Clod of Clay heard the Worms voice & rais'd her pitying head:
She bowd over the weeping infant, and her life exhald
In milky fondness, then on Thel she fix'd her humble eyes

O beauty of the vales of Har, we live not for ourselves,
Thou seest me the meanest thing, and so I am indeed:
My bosom of itself is cold, and of itself is dark,

But he that loves the lowly, pours his oil upon my head
And kisses me, and binds his nuptial bands around my breast.
And says; Thou mother of my children, I have loved thee
And I have given thee a crown that none can take away.

But how this is sweet maid, I know not, and I cannot know
I ponder, and I cannot ponder; yet I live and love.

The daughter of beauty wip'd her pitying tears with her white veil,
And said, Alas! I knew not this, and therefore did I weep:
That God would love a Worm I knew, and punish the evil foot
That wilful bruis'd its helpless form: but that he cherish'd it
With milk and oil I never knew, and therefore did I weep,
And I complaind in the mild air, because I fade away.
And lay me down in thy cold bed, and leave my shining lot.

Queen of the vales, the matron Clay answered: I heard thy sighs.
And all thy moans flew o'er my roof, but I have call'd them down:
Wilt thou O Queen enter my house, tis given thee to enter,
And to return: fear nothing, enter with thy virgin feet.

(Wikisource)

There are three figures here: in the top is the cloud like a naked male
flying and waving goodbye to Thel, the larger figure taking up most of
of the picture. The cloud has just introduced the worm, the small figure
at the bottom of the picture; it's in the middle of the lily cluster.

Thel sees the worm like a weeping infant.

The Clod of Clay also sees the (infant) worm and heard it weeping.  She
provides a motherly 'milky fondness' (worms generally live in clay). Then
she looked at Thel and told her "we live not for ourselves".

We might suppose that the life of a clod of clay must be pretty attenuated, and we 
might well conclude that generosity and love must be the foundation of the world.

Thel explains again, this time to the Clod of Clay why she had complained, and the 
Clod invites her to come on and live (mortally): 

"Wilt thou O Queen enter my house, tis given thee to enter,
And to return: fear nothing, enter with thy virgin feet."