Surah 2. Al-Baqara, Ayah 168

We now come to the regulations about food. First (ii. 168-71) we have an appeal to all people, Muslims, Pagans, as well as the People of the Book; then (ii. 172-73) to the Muslims specially; then (ii 174-76) to the sort of men who then (as some do now) either believe in too much formalism or believe in no restrictions at all. Islam follows the Golden Mean. All well-regulated societies lay down reasonable limitations. These become incumbent on all loyal members of any given society, and show what is "lawful" in that society. But if the limitations are reasonable, as they should be, the "lawful" will also coincide more and more with what is "good."