The person who practices sin belongs to the devil, because the devil has been sinning since the beginning. God's Son appeared for this purpose: to destroy the works of the devil.
Those born from God don't practice sin because God's DNA remains in them. They can't sin because they are born from God.
References for 1 John 3:9
This is how God's children and the devil's children are apparent: everyone who doesn't practice righteousness is not from God, including the person who doesn't love a brother or sister.