The term 'autonomy', from the Greek roots 'autos' and 'nomos' [self + law] refers to the right or capacity of individuals to govern themselves. Agents may be said to be autonomous if their actions are truly their own, if they may be said to possess moral liberty. The necessity of this moral liberty is made clear in the work of many philosophers in that of Kant, for example, Kant's ethical theory, in which the possession of autonomy of the will is a necessary condition of moral agency. For Kant, autonomy functions as the ability to know what morality requires of us, rather than as the freedom to pursue our ends. The possession of autonomy permits an agent to act on objective and universally valid rules of conduct certified by reason alone.
The major nonconsequentialist theory of reasoning based on Kantian theory states that what is imperative is duty above all. "Kant argues that moral truth stands by itself; it is autonomous and self-contained." (100) Actual success is not important what is important is that one accepts one's duty and attempts to fulfill their duty, duty above all, duty above emotion, above environmental or social influxes, even above God. Through reasoning and reason alone should be the basis for moral truth. Because of this absolute moral truth Kant's ethical system has some components which are compatible with Christianity. For instance, Christians believe in the absolute truth of God. The commands of God are nonnegotiable to be followed regardless of who it offends or how one feels about the situation. The rules are to be followed because they are rules and to Kantians that is what rules are for, to be followed.
On the flip side there is Divine Command Theory, based on faith. "It" exists because God created it and that is the end of the story. No being is truly free except for God because God is all powerful with no rules applying to him. Rules do not apply to him because no one has the authority to dictate to God which rules he must follow.