Shari'a and Christian Law

Christianity and Shari'a law share one similarity-- the philosophy behind each view of law acknowledges the existence of one God, and absolute morality, which stems from His will. However, in Islam, this God, and his absolute morality is ultimately unknowable, which is where the various differences between these two faiths' view of law stem from. Because Christians believe God has revealed Himself to man through merely the existence/nature of the universe and the Bible, God is in fact knowable, and the Christian view of law therefore stems from His knowable nature and moral code.
In Christian law, the absolute morality laid out both in the Bible and within the conscience of every human being provides the foundation for law. In Shari'a law, however, because the nature and morality of Allah are ultimately unknowable, the law (which is viewed as a means for keeping people on track with complete and total submission to Allah) prohibits any kind of indulgent behavior, and also limits what the rest of the world (and the Christian worldview) view as human rights. It is hyper-conservative because it, so to speak, doesn't know what is and isn't allowed-- what Allah does or doesn't want from man.
With the special revelation from God, the Bible, Christianity however has a much more clearly defined law. Christians believe that God's word lays out the principles of morality clearly so that they can be applied to law in consistent ways that don't rely on the interpretation of man, but rather on God's absolute truth.