The Bible also calls for the application of human free will to morality, as does Kant. Stories in the Bible reveal how human actors either obey or disobey the moral codes prescribed to them by the Biblical authorities, namely God. When God issues a "thou shalt," that moral law is ensconced. The person has free will, and therefore can be tricked by a malicious force symbolized by Satan. It is necessary to have free will for the categorical imperative to work, which is why there is the problem between good and evil in the first place. If it were easy for human beings to always do good, then Kant would have not had the impetus to write Groundwork for the Metaphysics of Morals. There would be an imperative to act, but it would not be categorical. Free will empowers the human being to make morally righteous choices, in accordance with the tenets of human reason.

One formulation of the categorical imperative that illustrates the concept is related to gay marriage. Interestingly, many "Bible thumpers" use the Mosaic law foundation as a means to bolster a spurious case against equality and human rights. Yet there is nothing in Mosaic law that prohibits gay marriage per se. Gay marriage as a sociological phenomenon did not exist at the time of the writing of the Bible: Hebrew or Christian. Therefore, one must look to the moral codes embedded in...

In this case, the imperative is to do right by all human beings. Universal truth and human rights are ensconced in the American Constitution as well as in the Bible. The ethically wrong act is barring equal access and preventing the extension of civil rights to all people. Kant would argue that it is irrational to confer a hetero-normative notion of marriage, because the imperative is not to support heterosexual patriarchal marriage but to support love and human liberties.
Gay marriage is a new social phenomenon, but it is a universal moral phenomenon. Kant's categorical imperative shows that it is always morally right to treat human beings with respect and to offer all human beings equal protection under the law. Prohibiting same-sex couples from having access to the same social institutions as straight couples is morally incorrect. There is a duty on behalf of all citizens to acknowledge this truth, which is rational, as opposed to the laws that are coded by bigots in positions of power. Bigots in positions of power have no moral jurisdiction or authority. For any moral code to work, it must be rooted in free will rather than coercion, and be phrased as an "ought," according to Kant. In this light, we "ought" to support love in all manifestations.