Just like in our ordinary life we receive the laws from the state or the king. The word given by the king or the state is accepted as law, and everyone has to abide by the law. Similarly, the order or the principle given by God is called religion. Religion without God is nonsense. Religion . . . because religion means the codes of God. So if one does not accept the existence of God, naturally he has no religion. And according to Vedic principle, a man without religion is an animal. Dharmeṇa hīna paśubhiḥ samānāḥ.
Because in every civilized form of human society, you will find some sort of religion. It may be Christian religion, it may be Hindu religion, it may be Buddhist religion or it may be Muhammadan religion, Jewish religion—it doesn't matter. Any civilized form of human society must have a sort of religion. Otherwise it is animal society.
What is the difference between animal and human being? The animals, they are engaged with the bodily necessities of life, āhāra-nidrā-bhaya-maithunam (Hitopadeśa 25): eating, sleeping—āhāra nidrā—and defending and sex life. These are the bodily necessities. You have to eat something, you have to sleep for some time, you have to defend yourself from others' attack, and you must have sex enjoyment. These are bodily necessities. So these bodily necessities are there in the human society and the animal society. Āhāra-nidrā-bhaya-maithunaṁ ca sāmānyam etad paśubhiḥ narāṇām.
Then what is the speciality of human society? The speciality of human society is that there must be some form of religion. In the animal society there cannot be any form of religion; therefore the śāstric injunction is that without any form of religion, a human society is animal society. Dharmeṇa hīna paśubhiḥ samānāḥ.