Machines were, it may be said, the weapon employed by the capitalists to quell the revolt of specialized labor.
— Karl Marx

What passions cannot music raise or quell?
John Dryden quelled quote

Disease an never be conquered, can never be quelled by emotion's willful screaming or faith's symbolic prayer. It can only be conquered by the energy of humanity and the cunning in the mind of man. In the patience of a Curie, in the enlightenment of a Faraday, a Rutherford, a Pasteur, a Nightingale, and all other apostles of light and cleanliness, rather than of a woebegone godliness, we shall find final deliverance from plague, pestilence, and famine.
— Sean O'Casey

...What are numbers knit By force or custom? Man who man would be,Must rule the empire of himself; in itMust be supreme, establishing his throneOn vanquished will, quelling the anarchyOf hopes and fears, being himself alone.
— Percy Bysshe Shelley

Although you may spend your life killing, You will not exhaust all your foes. But if you quell your own anger, your real enemy will be slain.
— quelled quotation by Siddha Nagarjuna