In James 2:19, we read, “You believe that there is one God. Good! Even the demons believe that—and shudder.”
When I first became a Christian, a pastor told me James 2:19 was referring to Jesus. Some years later, another pastor told me James 2:19 was also referring to the existence of God. So for years, I read James 2:19 as: You believe that Jesus exists. Good! Even the demons believe that and shudder. Or I read it as You believe there is a God. Good! Even the demons believe that and shudder. A plain reading of the verse says that the demons shudder because there is 1 God, not because there is a God, and Jesus is not even mentioned in this verse. So why was I reading it wrong? Because what we believe affects how we read and understand the Bible. This is why it is so important we allow the Bible to speak for itself. If we do not allow the Bible to speak for itself, we will miss out on something as important as what we should do to overcome and defeat the devil.
To understand James 2:19, we have to remember James did not have a New Testament. The Bible James used was the Old Testament which they believed was very relevant to them and the word of God. Paul even says to Timothy that we cannot be saved if we reject the Old Testament. Why? Because the Old Testament shows us how to be saved and how to live as saved people of God.
If we take Paul on his word, we will see how James 2:19 refers to Deut 6:4, which Jesus, in Mark 12:29, says is the most important commandment in the Bible: Shema Israel, Yehovah Eluheeno, Yehovah echad which translated to English is: Hear and obey Israel, Yehovah is our God, Yehovah is one. So what James and Jesus are trying to tell us is this: Our God Yehovah is one God, and this scares the demons. So can we do spiritual warfare and have victory over the devil as long as we believe God is one?
No, we have to read the entire chapter of James to understand what he is trying to say. And we have to understand what it means to believe God is one. To understand what it means to believe God is one, we have to go back to Deut 6:4, which says, hear and obey Israel, Yehovah is our God, Yehovah is one God. This is the first commandment in the law of Moses, so what Deut 6:4 is saying is this: Hear and obey Israel, Yehovah is our God, Yehovah is one, obey His law the law of Moses. So, according to Deut 6:4, if you want to have saving faith, you have to show you believe God is one by following His law.
If we read past James 2:19, he says it is not enough to believe God is one; you have to show you believe by obeying His law. He then says only the one who shows they believe God has saving faith in the cross. If it is not possible to see your faith in the oneness of God, then your faith in the cross is dead and unable to save you. But if it is possible to see your obedience to the law, then your faith in the oneness of God and your faith in the cross is visible living faith well able to save you.
This is what John says in Revelation 12 and 14; we see how the saints who obey the Mosaic law and believe Jesus died for them will overcome the devil. This is also what Paul says in the book of Romans, and Peter in his letters: Those who obey the law of Moses and believe Jesus died for them, will overcome the devil.
All of this is only visible to us if we allow the Bible to speak for itself, and we remember James, John, Peter, Paul, the Apostles, and Jesus did not have a New Testament. Their Bible, which they saw as very relevant and as the word of God, necessary for salvation, was the Old Testament.
Most Christians today see the Old Testament as irrelevant because they are New Testament Christians. They are unable to understand the Bible, and if you can’t understand the Bible, Paul says to Timothy, you have no way of knowing how to be saved and how to live saved. But what is more important is that you have no way of knowing how to do Biblical spiritual warfare.
The Bible clearly says spiritual warfare can only be done by living in obedience to the law of Moses with faith in the cross. Christians who obey the law and believe in the cross have heard and obeyed their God. And we know, from James 2:19, the demons tremble in fear because of one thing: The oneness of God and those who, because of the oneness of God, act on their faith being obedient to Yehovah.