I keep coming back to this post because something worries me a lot about it but I can't quite put my finger on it.
I think it might be to do with the idea that comes across in your post that God is like a strict parent: to be obeyed regardless. I think what CSL was trying to put across was that, perhaps for the Jews in the time of Moses he was, indeed, very much the Strict Parent - not at all to be questioned in anything . . but that our relationship with God has, and possibly still is (I mean on an individual basis), changing and that he has surrendered His royal throne and become our brother. The consequences of that are quite onerous in that it involves thought and decisions which are no longer the black and white of the Strict Parent. . . .
that means that we do indeed need to think rationally about our actions and apply sensitivity, experience and common sense so that, where potential wrong-doing is involved (such as in a sexual relationship with a minor) we can, on God's behalf, judge with fairness . . . .
It is one thing for me to decide for myself that God does not want me to become sexually involved with someone younger than 21 but, supposing one of my friends does? What will my view be on that? Will I judge with fairness or will I simply say 'It's wrong' and lock him up and throw away the key?
Does that make any sense?