The one who practices sin is of the devil, because the devil has been sinning from the very start. This is why the Son of God was revealed, to destroy the works of the devil.
KJV
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.
ASV
he that doeth sin is of the devil; for the devil sinneth from the beginning. To this end was the Son of God manifested, that he might destroy the works of the devil.
This shows who are God’s kids and who are the devil’s kids: the one who does not do right is not with God, and the one who does not love his brother or sister is not with God. ⚖️❤️
By this the children of God are distinguished from the children of the devil: Anyone who does not practice righteousness is not of God, nor is anyone who does not love his brother.
KJV
In this the children of God are manifest, and the children of the devil: whosoever doeth not righteousness is not of God, neither he that loveth not his brother.
ASV
In this the children of God are manifest, and the children of the devil: whosoever doeth not righteousness is not of God, neither he that loveth not his brother.