My take on 1 John 3:
7 Dear children, do not let anyone lead you astray. He who does what is right is righteous, just as he is righteous. 8 He who does what is sinful is of the devil, because the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the devil's work. 9 No one who is born of God will continue to sin, because God's seed remains in him; he cannot go on sinning, because he has been born of God. 10 This is how we know who the children of God are and who the children of the devil are: Anyone who does not do (have the habit of doing) what is right is not a child of God; nor is anyone who does not love (have the habit of loving) his brother
His seed within us affects us so that we are helped by God not to be characterized by a continuous walking in darkness. We do not "go on sinning."
He out of His graciousness grants us a reprieve and gives us periods of "joy unspeakable and full of glory."