The question for us now is simple. Is this New Testament Christianity? Are children of God formed from creation? By that I mean are we children of God just because we are created by God? Are we children of God just as a result of being born into this world? Are we children of God in the same way we are human beings? So being human equals being children of God - like TomAto/Tomato. Or are nice people God's children and bad people not so much? And if that's the case, who gets to decide who's in and who's out? How good to qualify and how bad to be disowned?
Fortunately for all of us this is a subject on which the New Testament speaks in abundance. And perhaps nowhere is the central doctrine of union with Christ more impacting and distinctive than right at this point.