We can go wrong in two directions when we talk about Satan. Either we don't take his existence and malign intention seriously enough, or we give him too much credit. The devil can't implant thoughts into your mind. The Bible teaches that the devil is a created being and that he tempts through suggestion and arguments. For instance [in] Matthew 4, what we see there is that Satan's a scripture twister. Satan isn’t original. He doesn't write scripts. He's never written the book. He doesn't know how to paint anything. He doesn't know how to create anything, he can't create anything, he distorts the Word of God, he runs around with spray paint spray painting over the Mona Lisa. The only way we discern Satan's voice is to know God's voice better.
It's often said [by] people who counteract the counterfeiting industry that the best way of being able to tell a counterfeit bill is to know the real thing really well. Jesus says “My sheep hear My voice and they follow me” To really know His voice, to know what his Word has said, to know the scriptures well enough, to know what he's truly saying, is the most important thing we can do because Satan is a pretty good theologian. Satan knows the Bible too. And Satan twists Scripture, he distorts Scripture.
We have to know what Scripture says in order to be able to discern when he's twisting it, but we also twist Scripture ourselves. I don't think it's very easy to distinguish. I can’t in my own life distinguish between Satan and my flesh. In either case, I think that Satan is taking advantage of the weakness of my sinful nature. But ultimately it's my sinful nature that gives him fodder and makes me susceptible to his temptation and to his false teaching. In Ephesians 6, Paul tells us that the sword of the Spirit, which is the Word of God, is our offensive weapon here. The defensive weapon is the perfect righteousness of Christ.
When Satan comes to you and when he tempts you into thinking that you really don't have a genuine conversion experience because you haven't experienced the Lord the way other people have, or because you are struggling with the same sin over and over again, that's what Satan focuses on when he comes with those criticisms. He'll even quote Scripture out of context. Do you say then, “let me have a conversation with you, Satan, about my Christian experience? It's a lot better than you think it is.” No, you put on Christ. Don't go reach for your righteousness in a conversation with the accuser of the brethren. Put on the righteousness of Christ as a breastplate and his arrows won't penetrate. Put on the helmet of salvation, the objective work of Christ. Satan can't do anything about that. Jesus said, “It is finished” from the cross, and it is. Satan can’t undo that.
Take up the sword of the Spirit, which is the Word of God and the shield of faith, not, again, appealing to your good works but the shield of faith, faith in Christ. This is how we stand the assault of the enemy in our lives. The front line of this warfare is false teaching. That's what Satan really majors in.
“Beloved, do not believe every spirit but test the spirits to see whether they are from God. For many false prophets have gone out into the world by this you know the Spirit of God, every spirit that confesses that Jesus Christ is come in the flesh is from God. And every spirit that does not confess Jesus, is not from God” (1 John 4 1:1-2).
Adapted from an answer given on Episode 146 of the Core Christianity Radio Show.