'It is impossible for the mind not to be approached by
thoughts, but it is in the power of every earnest man either to admit
them or to reject them. As then their rising up does not entirely depend
on ourselves, so the rejection or admission of them lies in our own
power. But because we said that it is impossible for the mind not to be
approached by thoughts, you must not lay everything to the charge of the
assault, or to those spirits who strive to instil them into us, else
there would not remain any free will in man, nor would efforts for our
improvement be in our power: but it is, I say, to a great extent in our
power to improve the character of our thoughts and to let either holy
and spiritual thoughts or earthly ones grow up in our hearts. For for
this purpose frequent reading and continual meditation on the Scriptures
is employed that from thence an opportunity for spiritual recollection
may be given to us, therefore the frequent singing of Psalms is used,
that thence constant feelings of compunction may be provided, and
earnest vigils and fasts and prayers, that the mind may be brought low
and not mind earthly things, but contemplate things celestial, for if
these things are dropped and carelessness creeps on us, the mind being
hardened with the foulness of sin is sure to incline in a carnal
direction and fall away.'