Karma is that which we have written ourselves and through habituation from parents and parents of parents, picked up on an instinctual level from them (the ones who wean us into this world), and thusly write into our physicality the instinctual memories of these things for survival, which of course 99.99% is totally not true (but is true of course pertaining to the reality for which it is seen and seemingly applied; theories of how things work and the universe works, and thusly, acts in kind per type of interaction and response).
This is in a sense "against" God only in that God is a consciousness, this awareness and attunement that rises "above" this level awareness and animalistic impression level (nature of incarnation).
This does not mean incarnation is evil or against God. It's part of God. The part called Grace is taht which is the energetic attunement "above" this karmic aspect and thusly is something that lifts you above the torture of that level and awareness degree.