Lets say the physics laws eg. what goes up must come
down....
And the Karmic law : Good begets good and evil begets
evil...
You are assigning names like "law" and "God".... dun assign and
your mind shall be free....
Its so difficult to explain to you becos u do not have the
essential buddhist knowledge....sorry....I can't and dunno how to
explain to you....Hahaha! 
Demon Bane,
The laws of gravity are such because God established them
and upholds them. That's why the universe is intelligible and we
can go about our science and discover how things work, because God
who is rational and orderly created the world to be such.
I am no more assigning names than you are in calling things
"karma", "good", "evil". We should not despise the use of words,
they are meaningful for communication.
I do have some knowledge of Buddhism, and there's no harm trying
to explain things as simple as possible to the best of your
ability. That's what I have been doing anyway for the Christian
faith.