In the spiritual realm and of the soul, the devil is allowed to be involved at certain levels and in certain ways. St. John of the Cross proposed what consists of the levels or "rings" of the soul. Further, there are certain levels or rings to which God allows the devil access.
Why allow access to areas of our souls? It is the Lord's way of strengthening us in faith, in learning how to combat the forces of this temporal life, in learning how to grow in the spiritual life, and in allowing us to progress as souls in preparation for eternal life with the goal of heaven: spiritual perfection and union with Christ.
In spiritual combat, the Lord gives us all manner of assistance. But for the purposes in this post, I simply want to explain the diagram of the levels or rings of the soul and give some examples of how the devil is allowed to involve himself in these areas.
Picture in your mind a large circle with smaller circles going inward, circle or ring by ring until the very center circle. This entire large circles with rings gradating toward a center circle, represents our souls.
The outer ring represents the senses. God allows the devil to involve himself with our senses, to tempt us at the physical sense level: what we see hear, touch, say, smell as well as all temporal objects and physical situations, pain, pleasure, actions, and through objects.
The next ring represents the emotions. God allows the devil access to interfere with our emotions, our feelings. The devil does this through creating upset, disturbance, extremes in sorrow as well as in happiness. Yes, extremes--the devil works through utilizing extremes especially with emotions.
The third ring inward represents imagination, or images. God allows the devil to create images such as false visions, distressing dreams, horrific scenes in our inner sight, and also to warp our "imaginations" with a variety of visual effects.
The fourth ring represents memory. Ah, how successful the devil can be when allowed to induce thoughts of the past--longings and inner remembrances of how things used to be either better or worse, whatever disturbs the soul the most.
The fifth ring represents knowledge. God lets the devil try us by presenting false ideas, false facts, distorted information, and also tempts our pride that we have superior knowledge when, in truth, we do not. The devil uses the knowledge we have to give a sense of confidence in what knowledge we think we have, and then let us fall flat.
The sixth ring represents understanding. God allows the devil access to our understanding, for what better and higher-level area of being than to confuse that which we understand, as understanding is one of the gifts of the Holy Spirit? By testing our understanding under hell-fire, we face ultimate conquest or derision.
The center ring of our souls contains two aspects: our intellect and our will. The will is in closer proximity to the center of all creation, the center from which we proceed forthwith, from God the Father, God the Son, God the Holy Spirit. The devil is not allowed access nor involvement with this center area or ring of our soul. God keeps the intellect and will protected. Thus, there is nothing the devil can do to disrupt our wills or our intellects.
All the other aspects are the areas in which the devil can interfere, and if we are not watchful, if we do not learn spiritual combat techniques, it is through our senses, emotions, imaginations, memory, knowledge, understanding--that influence and cause us to, by our own intellects and our own free wills, to cave to these other influences. But as far as the will and intellect, the devil is not allowed access. The damage comes when we do not combat the deceptions and disruptions that evil can cause in the outer rings or lower levels of our souls.
How is this, then, that our will and our intellect are off-limits to the devil? In this innermost part of our souls, the very center of our souls, while the will and intellect are each within, it is the will that is in first position, or primary, and closest to our Source: God. Our intellect is interconnected; and at its best and height of spiritual progression, the intellect unites with the will in a ceaseless cooperative interaction with God.
When (and we ought pray for this grace and actual occurrence) our will and our intellect become God's, or rather, more technically when God's Will and God's Mind flows and fills ours--in effect replacing our will and intellect, usually one and then the other--then there is supreme, holy cooperation and providential grace in action.
Divine Union occurs when the totality of our soul becomes one with God, and this does not happen in our earthly lifetimes or would be quite rare if possible. The senses, while being usually the first area that the devil works his tricks on us, is that which gets in the way of Divine Union while yet alive. This is rather obvious, since our bodies bind us to this life until we die.
However, other aspects of our souls, other levels, may have union with God even if briefly, while we are yet in our mortal bodies. And in some instances, some aspect or other or more may over time, find union with God while we yet are on earth. The process termed purgatory is the continuation of our soul progression.
Well, I am verging into far more than that of this post's topic: the devil's involvement in our souls, what God allows, and brief explanation. Simply being aware of these aspects of our souls and the various ways in which they interact and also how we can be deceived, is quite helpful in combatting successfully, the devil's attempts to get our intellects and wills to sin or ultimately, to ruin our eternity in union with God.
God bless His Real Presence in us! Turn away from evil and do good! Praise God in all things and love one another as Jesus loves us!