It must be emphasised that, on its own, esoteric training does not improve people. Although one may have acquired moral virtues, or reached high levels of intellectual development, he may still possess within his soul unbalanced bad characteristics, concealed by conventional morality. We are actually worse than we think we are. During esoteric development, when a man takes himself in hand, hidden vices are inevitably exposed. All the esotericist’s strength will then be needed to overcome them.
Source (German): Rudolf Steiner – GA 266b – Aus den Inhalten der esoterischen Stunden – Band II: 1910 – 1912 – Stuttgart, February 23, 1912 (page 336)