A Target Of Satan
Charles Finney seemed to be speaking from personal experience as he addressed genuine followers of Christ in his sermon "On Being Filled With the Spirit":
"You must expect very frequent and agonizing conflicts with Satan. Satan has very little trouble with those Christians who are not spiritual, but lukewarm, and slothful, and worldly-minded (and in danger of apostasy - GC). And such do not understand what is said about spiritual conflicts. Perhaps they will smile when such things are mentioned. And so the devil lets them alone. They do not disturb him, nor he them. But spiritual Christians, he understands very well, are doing him a vast injury, and, therefore, he sets himself against them. Such Christians often have terrible conflicts. They have temptations that they never thought of before, blasphemous thoughts, atheism, suggestions to do deeds of wickedness, to destroy their own lives, and the like. And if you are spiritual, you may expect these terrible conflicts.
You will have greater conflicts with yourself than you ever thought of. You will sometimes find your own corruptions making strange headway against the Spirit. "The flesh lusteth against the Spirit, and the Spirit against the flesh." Such a Christian is often thrown into consternation at the power of his own corruptions. One of the Commodores in the United States was, as I have been told, a spiritual man; and his pastor told me he had known that man lie on the floor and groan a great part of the night, in conflict with his own corruptions, and to cry to God in agony that he would break the power of the temptation. It seemed as if the devil was determined to ruin him; and his own feelings, for the time being, was almost in league with the devil."
But feelings and thoughts do not determine our character - our choices do. Evil spirits can can oppress us and cause doubts and fears, but they cannot override the will. Resist. Reject the devil's lies. Follow Christ.