Christian, dont have and I think never had scripts as rigourous and as authentic as the muslims scripts, this is why in christianity when the pope rule its the pope will

1) The pope rules Catholics, not Christians. Catholicism is a subsect of Christianity.

2) As I understand it, the Quran considers the religions of Christianity and Judaism to be "Followers of the Book" as well, meaning that their "scripts" are God-given word just as the Quran is. Hence, strict Islam should not consider its own scripts any more rigorous or authentic; merely later and/or more detailed.