Notes from an American University website (author unknown):
Queen Mab was published May 1813 and was Shelley's first major production. Queen Mab was considered subversive and radical. It's main targets were established religion, political tyranny, the destructive force of war and commerce, and the perversion of human love caused by such chains and barriers as the marriage institution and prostitution. Secondary themes were temperance, vegetarianism, and republicanism. What Shelley was preaching came to be understood as a "vision of the good life built on atheism, free love, republicanism, and vegetarianism."

from Queen Mab:

. . . . . . . . . . . . No longer now
He slays the lamb that looks him in the face,
And horribly devours his mangled flesh;
Which, still avenging nature's broken law,
Kindled all putrid humours in his frame,
All evil passions, and all vain belief,
Hatred, despair, and loathing in his mind,
The germs of misery, death, disease, and crime.
No longer now the winged habitants,
That in the woods their sweet lives sing away,
Flee from the form of man; but gather round,
And prune their sunny feathers on the hands
Which little children stretch in friendly sport
Towards these dreadless partners of their play.

from Queen Mab:

How strange is human pride!
I tell thee that those living things,
To whom the fragile blade of grass,
That springeth in the morn
And perisheth ere noon
Is an unbounded world;
I tell thee that those viewless beings,
Whose mansion is the smallest particle
Of the impassive atmosphere,
Think, feel and live like man;
That their affections and antipathies,
Like his, produce the laws
Ruling their moral state;
And the minutest throb
That through their frame diffuses
The slightest, faintest motion,
Is fixed and indispensable
As the majestic laws
That rule yon rolling orbs.

from The Revolt of Islam:

Never again may blood of bird or beast
Stain with its venomous stream a human feast,
To the pure skies in accusation steaming.

from Alastor or The Spirit of Solitude:

Earth, ocean, air, beloved brotherhood!
If our great Mother has imbued my soul
With aught of natural piety to feel
Your love, and recompense the boon with mine;
If dewy morn, and odorous noon, and even,
With sunset and its gorgeous ministers,
And solemn midnight's tingling silentness;
If autumn's hollow sighs in the sere wood,
And winter robing with pure snow and crowns
Of starry ice the gray grass and bare boughs;
If spring's voluptuous pantings, when she breathes
Her first sweet kisses, have been dear to me;
If no bright bird, insect, or gentle beast
I consciously have injured, but still loved
And cherished these my kindred - then forgive
This boast, beloved brethren, and withdraw
No portion of your wonted favour now

from Prometheus Unbound:

I wish no living thing to suffer pain.