The Qu'ran does not say that "Christians" will be punished but the followers of a tainted form (Muslim viewpoint) of Christianity (the view that the doctrine of Trinity was created by humans and Jesus was gradually elevated from status of prophet to the son of God - see the sentence directly above as to how we believe that happened: '''However, the Qur'an warns against worshipping Jesus, Muhammad, and other human for fear of idolatry.[8]''')
I just wanted to point that out because the current wording makes it sound as if Allah were saying that people who followed the previous prophet he sent would be punished which makes absolutely no sense from a Muslim viewpoint.~~