Discord

Discord lack of agreement among persons, groups, or things. Tension or strife resulting from a lack of agreement; dissension. A confused or harsh sound or mingling of sounds. In music, an inharmonious combination of simultaneously sounded tones; a dissonance

Sourced

• From hence, let fierce contending nations know
  What dire effects from civil discord flow.
  • Joseph Addison (1672–1719). Cato (1712), Act v. Sc. 4

• Take but degree away, untune that string,
  And, hark, what discord follows! each thing meets
  In mere oppugnancy.
  • William Shakespeare (1564–1616). Troilus and Cressida (1602), Act i. Sc. 3

• All your strength is in your union
  All your danger is in discord;
  Therefore be at peace henceforward,
  And as brothers live together.
  • Henry Wadsworth Longfellow (1807–1882). The Song of Hiawatha (1855), Part i

Unsourced

• The peacemakers shall be called the sons of God, who came to make peace between God and man. What then shall the sowers of discord be called, but the children of the devil? And what must they look for but their father's portion?
  • Bernard of Clairvaux

• Our life is full of discord; but by forbearance and virtue this same discord can be turned to harmony.
  • James Ellis