Read 1 John 3:8 Using Other Translations
He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.
Whoever makes a practice of sinning is of the devil, for the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the works of the devil.
But when people keep on sinning, it shows that they belong to the devil, who has been sinning since the beginning. But the Son of God came to destroy the works of the devil.