The second sentence of Surah al-Ma’idah ayah 5 says,
وَطَعَامُ الَّذِينَ أُوتُواْ الْكِتَـبَ حِلٌّ لَّكُمْ وَطَعَامُكُمْ حِلٌّ لَّهُمْ
“The food of the People of the Scripture is lawful to you, and your food is lawful to them.”
According to the consensus of Sahabah and Tabieen, the word Ta’am [food] at this place means ‘properly slaughtered animals’. This is what has been reported from Abdullah ibn Abbas, Abu ad-Darda, Ibraheem Qatadah, al-Suddi, Dhahhak and Mujahid, may Allah be pleased with them all, because in foods of all other kinds, the People of the Book and the idolators and all other disbelievers are just the same as bread, flour, lentils, beans, rice, fruits and similar other eatables need no slaughtering.
For Muslims, eating that kind of food, of course, when procured by any lawful means, is permissible – and conversely, when they procure it from Muslims, it is lawful for them. Thus, the essence of the sentence is that the Zabeehah of the People of the Book is lawful for Muslims and the Zabeehah of Muslims is lawful for the People of the Book.
People of the Book are the Jews and the Christians. One may ask, does this mean those who genuinely believe in the “original” Torah and Injeel and act in accordance with these? Or, even those who follow the altered Torah and Injeel and those who ascribe to Eesa aalyhi salaam and Mariyum aalyhi salaam, partnership in the Divinity of God, shall be deemed as included among the People of the Book? The answer is that it is quite evident from the many clarifications of the Qur’an that for a people to be from ‘The People of the Book’, it is quite enough that they accept and believe in a Scripture and claim to follow it – irrespective of how much astray they may have gone while following it.
Those to whom the Qur’an has given the title of the People of the Book were also those about whom it said at several places that these people distort their Scriptures [5:13]. It also said that the Jews took Uzair aalyhi salaam as the son of God and the Christians did the same to Eesa aalyhi salaam.
When despite what they were and what they did, the Qur’an insisted on calling them the People of the Book, it becomes evident that unless the Jews and Christians were to abandon Judaism and Christianity totally they shall continue to be the People of the Book, no matter how involved in false beliefs of their religion and dark doings they may be.
Imam al-Jassas reports in Ahkam-ul-Qur’an that during the khilafah of Umar radhiAllahu anhu one of his governors wrote to him for advice. He said that there were some people in his area who recited the Torah and observed the Sabbath like the Jews but they did not believe in Qiyamah. He wanted to know how he was supposed to deal with such people. Umar radhiAllahu anhu wrote back telling him that they will be taken as a sect of the People of the Book.
[SOURCE: Maroof-ul-Qur’an by Mufti Muhammad Shafi Usmani]