....the obligatory prayers are by their very nature of
greater effectiveness and are endowed with a greater power than the
non-obligatory ones, and as such are essential.
(From a letter dated 4 January
1936 written on behalf of Shoghi Effendi to an individual believer, published
in "Bahá'í News" 102, August 1936; The Compilation of Compilations,
Vol. II, The Importance of Prayer, Meditation and the Devotional Attitude)
