Know, that in this unseen warfare, two wills existing in us fight against one another: one belongs to the intelligent [noetic] part of our soul and is therefore called the intelligent [noetic] will, which is the higher; the other belongs to the sensory part and is therefore called the sensory will, which is the lower. The latter is more frequently called the dumb, carnal, passionate will. The higher will is always desiring nothing but good, the lower – nothing but evil. Each equally happens by itself; so that neither is a good desire in itself reckoned as good, nor an evil desire as evil. The reckoning depends upon the inclination of our own free will. Therefore, when our will inclines towards a good desire, it is reckoned in our favor; but when we incline toward an evil desire, it is reckoned against us. These desires follow one upon another: when a good desire comes, an evil desire immediately opposes it; and when an evil desire comes, a good desire at once rises against it. Our will is free to follow the one and the other, and whatever desire our will inclines towards, it becomes victorious on this particular occasion. It is in this that all our unseen spiritual warfare consists.
Book: Unseen Warfare ~ Chapter Twelve