Little children, make sure no one deceives you; the one who practices righteousness is righteous, just as He is righteous; the one who practices sin is of the devil; for the devil has sinned from the beginning. The Son of God appeared for this purpose, to destroy the works of the devil. (1 John 3:7-8)
When verse 8 says, “The Son of God appeared [deity – clothed with humanity and born of virgin -who walked in obedience, laid down his life and rose from the dead] for this purpose, to destroy the works of the devil,” what are the “works of the devil” that he has in mind? The answer is clear from the context.
First, verse 5 is a clear parallel: “You know that He appeared in order to take away sins.” The phrase “he appeared to . . .” occurs in verse 5 and verse 8. So probably the “works of the devil” that Jesus came to destroy are sins. The first part of verse 8 makes this virtually certain: “The one who practices sin is of the devil; for the devil has sinned from the beginning.”
The issue in this context is sinning, not sickness or broken cars or messed up schedules. Jesus came into the world to help us stop sinning.
let me put it alongside the truth of 1 John 2:1: “My little children, I am writing these things to you so that you may not sin.” In other words, I am promoting the purpose of Christmas (3:8), the purpose of the incarnation. Then he adds (2:2), “And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous, and He Himself is the propitiation for our sins; and not for ours only, but also for those of the whole world.”
But now look what this means: it means that Jesus appeared in the world for two reasons. He came that we might not go on sinning; and he came to die so that there would be a propitiation [a substitutionary sacrifice that takes away the wrath of God] for our sins, if we do sin.
— John Piper, Solid Joys devotional; an excerpt from his sermon, The Son of God Appeared to Destroy the Works of the Devil.