Many sects of Christendom, along with many other religions, believe that there is a being or monster called the Devil or Satan who is the originator of the problems which are in the world and in our own lives, and who is responsible for the sin which we commit.
The Bible clearly teaches that God is all-powerful. We have seen in that the Angels cannot sin. If we truly believe these things, then it is impossible that there is any supernatural being at work in this universe that is opposed to Almighty God. If we believe that such a being does exist, then surely we are questioning the supremacy of God Almighty. This issue is so important that the correct understanding of the devil and Satan must be considered a vital doctrine.
We are told in Heb**rews**.2:14 that Jesus destroyed the devil by his death; therefore unless we have a correct understanding of the devil, we cannot understand the work or nature of Jesus.