Slavoj Zizek writing for ABC Religion and Ethics (Apr 17 2012): 

[t]he religious suspension of the ethical was already proposed by Augustine who wrote, “Love God and do as you please” (or, in another version, “Love, and do whatever you want” - from the Christian perspective, the two ultimately amount to the same, since God is love). The catch, of course, is that, if you really love God, you will want what he wants - what pleases him will please you, and what displeases him will make you miserable. So it is not that you can just “do whatever you want” - your love for God, if authentic, guarantees that, in what you want to do, you will follow the highest ethical standards.

…However, the ambiguity persists, since there is no guarantee, external to your belief, of what God really wants you to do - in the absence of any ethical standards external to your belief in and love for God, the danger is always lurking that you will use your love of God as the legitimization of the most horrible deeds.

…If the gift of Christ is to make us radically free, then this freedom also brings the heavy burden of total responsibility.