Should Christians be described as infidels (kuffar) or polytheists (mushrikin) or People of the Book (Ahl al-Dhimma), and is it permissible to describe them as infidels in view of His, the Almighty’s, saying: "Certainly, disbelievers are those who say, 'Allah is the Messiah, son of Mary'"?

Disbelief (kufr) and polytheism (shirk) are intertwined, and the People of the Book (Jews and Christians) are characterized by both. Their attribute of disbelief is mentioned in verses such as: "Those who disbelieved among the People of the Scripture and the polytheists were not to be parted [from disbelief]" [Al-Bayyinah: 1]. As for their attribute of polytheism, it is evident in Allah's saying: "They have taken their scholars and monks as lords besides Allah, and [also] the Messiah, son of Mary" [At-Tawbah: 31], and for their attribution of a companion and a son to Allah.