The secret of Zen is just two words: not always so.
[In Japanese it is two words]
Suzuki Roshi
Jung [said]..: “A psychoneurosis must be understood, ultimately, as the suffering of a soul which has not yet discovered its meaning.” Notice that he does not rule out suffering, for suffering, the medieval adage had it, “is the fastest horse to completion.”
The clear implication of Jung’s position is that working through one’s way to meaning – that is, to an enlarged view of ones dilemma and perhaps to an enlarged view of one’s own summons – can lead one through the valley of the shadow.
James Hollis, Living an Examined Life: Wisdom For the Second Half of the Journey.
(The interesting medieval idea he refers to is from Meister Eckhart: The quickest horse that carries you to perfection is suffering)