They [1] must strive to obtain, from sources that are authoritative
and unbiased, a sound knowledge of the history and tenets of Islam -- the
source and background of their Faith -- and approach reverently and with a mind
purged from preconceived ideas the study of the Qur'án which, apart from the
sacred scriptures of the Bábí and Bahá'í Revelations, constitutes the only Book
which can be regarded as an absolutely authenticated Repository of the Word of
God.
- Shoghi Effendi ('The Advent of Divine Justice’)
[1] Those who participate in a teaching campaign
