Occasionally I will be asked, "How can I know if my thinking is in harmony with what God really wants, or is it just me or even Satan?" It is extremely important to recognize the
difference and know how to discern God's voice, because it has eternal consequences.
In fact, sometimes evil gets blamed on God when people say, "God told me to do it!" The Bible says in 1 John 4:1, "Don't always believe every message you hear just because someone says it is a message from God; test it first to see if it really is" (TLB).
God will never contradict his Word. God doesn't say one thing and then change his mind and say another. If He said it, it's true, and it will always be true. God is consistent. He isn't moody. He will never tell you to violate a principle that He's already given in His Word, the Bible. Therefore, the first question you need to ask is, "Does this thought line up with what God has already said?" If what's in your mind contradicts something that God has already said in the Bible, then you know it's wrong.
Jesus said in Luke 21:33, "Heaven and earth will pass away, but my words will never pass away" (NIV). God's Word is eternal; truth never changes. If something was true 5,000 years ago, it is true today, and it will be true forever!
People say, in fact I've said it, "God said it, I believe it, and that settles it." That's true, yet rather I believe it or not does not determine it's truth. If God said it, that settles it!
Always ask yourself, "Is this idea in harmony with the Word of God?" If it is, go for it - if not, pray a little longer!