Hmm. Depends on how you intrepret "guarantee". Our civil rights are granted by God, as recognized in the Declaration of Independence:
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, ...
But history tells us that very often, people have not actually enjoyed the free exercise of these rights. So, again according to the DoI:
That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, ....
So, is the "guarantee" the endowment of these rights, or the securing of them? God does the former, and governments are established for the latter.