Man in this age has learned the weight of the sun, the path
of a star, the movement of an eclipse -- the advance step now is to learn the
expansion of the inflexible law of matter into the subtler kingdom of spirit,
which contains a finer gravitation which holds the balance of power from age to
age unbroken. Blessed is that soul who knows that against all appearances, the
nature of things works for truth and right forever… The emancipated soul sees
with the eyes of perfect faith because it knows what vast provisions are made
to enable it to gain the victory over every difficulty and trial. Yet man must
ever remember the earth plane is a workshop, not an art gallery for the
exhibits of powers. This is not the plane of perfection, but earth is the
crucible for refining and moulding character."
- ‘Abdu’l-Baha (‘The Baha’i Magazine', vol, 24, no. 11, February, 1934)