In regard to the main question you have raised in connection
with the singing of hymns at Bahá'í meetings: He wishes me to assure you that
he sees no objection to it whatsoever. The element of music is, no doubt, an
important feature of all Bahá'í gatherings. The Master Himself has emphasized
its importance. But the friends should in this, as well as in all other things,
not pass beyond the limits of moderation, and should take great care to
maintain the strict spiritual character of all their gatherings. Music should
lead to spirituality, and provided it creates such an atmosphere there can be
no objection against it. A distinction of vital importance should, however, be
clearly established between the singing of hymns composed by the believers and
the chanting of the Holy Utterances.
(From a letter dated 17 March 1935 written
on behalf of Shoghi Effendi to an individual believer; The Compilation of
Compilations, vol. III, The Importance of Arts in Promoting the Faith)