Whatever is in the heart of man, melody moves and awakens.
If a heart full of good feelings and a pure voice are joined together, a great
effect is produced. For instance: if there be love in the heart, through
melody, it will increase until its intensity can scarcely be borne; but if bad
thoughts are in the heart, such as hatred, it will increase and multiply. For
instance: the music used in war awakens the desire for bloodshed. The meaning is
that melody causes whatever feeling is in the heart to increase.
('Abdu'l-Bahá's words to Mrs. Mary L. Lucas, as quoted in "A Brief Account
of My Visit to Acca" (Chicago: Bahá'í Publishing Society, 1905); The Compilation of Compilations vol II) (To read the entire talk
please visit Talks of
‘Abdu’l-Baha)