Our work is to "resist the devil," not harbor his doubts; and if we do this, the promise is "he will flee from you."
But the question is often asked, How can I resist Satan? There is only one way by which you can do this, and that is by faith, taking Christ as your helper and pleading with Him for strength. When Satan suggests doubt to your soul, when he tells you that you are too unworthy, too sinful, to realize the blessing of God, present Christ before him as your Advocate and Saviour. Tell him you know that you are a sinner, but that Jesus came to seek and save that which was lost. He came "not to call the righteous, but sinners to repentance" (Mark 2:17).
Repeat His promises: "Him that cometh to me I will in no wise cast out" (John 6:37). . . . "Let him take hold of my strength, that he may make peace with me; and he shall make peace with me" (Isa. 27:5). "Whatsoever ye shall ask in prayer, believing, ye shall receive" (Matt. 21:22). Be simplehearted enough to believe these promises of God. When Satan comes to you, and tells you that because you are unhappy, perplexed, and troubled you are not a child of God, do not become discouraged for one moment, but gird up the loins of your mind. Let your heart repose in God. He has promised that if you come to Him, you shall find rest to your soul; and if you have done this, rest assured that He will fulfill His word in you....
Many pass long years in darkness and doubt because they do not feel as they desire. But feeling has nothing to do with faith. That faith which works by love and purifies the soul is not a matter of impulse. It ventures out upon the promises of God, firmly believing that what He has said, He is able also to perform. Our souls may be trained to believe, taught to rely upon the Word of God. That Word declares that "the just shall live by faith" (Rom. 1:17), not by feeling. That I May Know Him 245
Confederacies will increase in number and power as we draw nearer to the end of time… There needs to be much more of prayer, much more of earnest effort, among professed believers. Pr 27.
Therefore submit to God. Resist the devil and he will flee from you. James 4:7 (New King James Version)