"In the soul we find three powers: the intellect, the will, the
heart, or, as the Holy Fathers say, the intellectual, desiring and
incensive powers. Each of them is assigned particular curative
exercises by the holy ascetics. These related excercises are
both receptive and conducive to grace. They need not be contrived
according to some theory, but rather chosen from tested ascetic
labors particularly suited to a given power:"
-St. Theophan the Recluse in "The Path To Salvation"
"The chief character of believing thought consists of the striving
to concentrate all the separate powers of the soul into a single
power, to seek out that inner focus of being where reason, will,
feeling and conscience, the beautiful and the true, the wonderful
and the desirable, the just and the merciful, and the whole sweep
of the mind are fused together in one living unity, thus restoring
the essential personality in its original indivisibility"
-Ivan Kiriyevksy (Optina disciple and key Orthodox Integral