Manual of The Mother Church/Church Services/Music in the Church
MUSIC IN THE CHURCH.
Soloist and Organist. Section 1. The music in The Mother Church shall not be operatic, but of an appropriate religious character, and of a recognized standard of musical excellence; it shall be played in a dignified and suitable manner. Music from the organ alone should continue about eight or nine minutes for the voluntary and six or seven minutes for the postlude, the offertory conforming to the time required to take the collection. The solo singer shall not neglect to sing any special hymn selected by the Board of Directors.