J.C. Ryle draws a picture of the devil’s work in his commentary on John. He points out that in verse 2 of this chapter the devil had already put the idea of Christ’s betrayal into Judas’ heart. Now, the devil entered Judas and he goes out to work the evil plan.
We are constantly bombarded by sin. John has shown that the three main assaults come from the devil, the world, and our own sinful desires. The devil knows our weaknesses and wants to destroy us. The world is full of sin and wants to pull us into it. We have our own sinful desires that our flesh desires to fulfill. We must fight each of these at the first point of contact. If we allow them a foothold then they can quickly take root and go to full bloom.
The great news is that we are not alone. We have the Holy Spirit and the Word. We are told if we resist the devil he will flee from us. We are in the world but Jesus has overcome the world. We are set free from slavery from sin by Jesus. Are you fighting sin at the first point of contact? The Christian will not be lost, but the consequences of sin can be very high.
Consider: James 4:7