The Submission of Our Sensuous Nature to the Moral Law in the Second Critique

Why should we submit the moral law, which is entirely incompatible with our inclinations, namely with our emotions, desires, and instincts such as self-love? After all these inclinations affect us quite strongly, for long period of time, and under various circumstances on a regular daily basis. In a synthetically a posteriori procedure, starting with the well-acknowledged fact that there is a deontologically moral behavior, such as the Kantian one, despite our antagonistic inclinations. What makes such a moral legislation possible is the undeniable fact that nature, including our sensuous nature, cannot legislate for itself. Had laws of nature or moral laws been given a posteriori and were not a priori product of our spontaneous, free reason, they have not been laws for us, because they were not products of our reason. Only such products are intelligible to us. As nature, including sensuous nature, cannot gives itself laws, scientific or moral, we have no alternative but to submit the moral laws whenever we freely decide not to follow our inclination or any given fact but use our reason, which is free from them, to follow the moral law.