1 John 3:8 …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.
What is the greatest destructive work of the devil - creating separation between man and his Creator. Jesus came to restore that breach - thus destroying the work of the devil. By Jesus' sacrifice the veil of separation was torn in two, from top to bottom, thereby restoring what had been separated, atonement had been made - complete restoration of that which the devil had instigated.
Sin is what separates us from God and it is the devil's longing that we be separated from Him. But the good news is that Jesus paid the price for our sin and we no longer have to live separated from God - the devil loses!
Jesus destroyed the works of the devil - do you believe it?