Any moral feeling has a short time of life. We or most of us cannot feel love, compassion, pity, generosity, and any other altruistic feeling for a long time.
Perhaps the moral rules were issued to ameliorate such a human lack in moral feelings, too. Though we loose our moral feelings, we know there are some norms which always preserve the morality.
They do not provide us those lost feelings or any feeling at all, but comfort us as regards the shame of abandoning others at once with the loss of our feelings for them. The moral rules possess that continuity we cannot approach and they falsely show that the moral feeling is not in fact a matter of loyalty to other men, but rather one of respect to abstract norms.
While the secular moral rules are debatable, the religious commandments impose themselves with a greater authority.
But do they help us more with the shame of abandoning others? It seems that they deepen our tendency of abandoning others more than secular rules do. Because they do not only replace the human temporary feelings with eternal moral laws, but also try to instill other feelings that make the first ones totally forgotten. These other feelings are those inspired by faith, which shows that we have not ultimately a duty for human beings, but for the divinity.