The Bible makes the claim: "All Scripture is inspired by God" (2 Tim. 3:16). Since God is perfect, it would stand to reason that His word is perfect.
This is exactly what we find with the Bible. Despite the fact that it was written by about 40 different authors in three different languages over a period of 1500 years, there is perfect harmony throughout. A proof that the Bible is a product of divine origin, not from the mind of man.
Contrast this with another book claiming to be of divine origin, the Qur'an. The Qur'an originated in the mind of man. As a result, it does not have the harmony found in the Bible. But those who wrote the Qur'an were clever. They provided a loophole to explain any contradiction:
"Whatever communications We abrogate or cause to be forgotten, We bring one better than it or like it. Do you know that Allah has power over all things?" (Qur'an 2:106)
So if you're a Muslim reading the Qur'an and find a passage that contradicts another, what do you do? Simple: believe whatever came later. After all, who's to say that Allah cannot change his mind? Personally, I would not expect fickle to be a characteristic of Almighty God.
The Bible needs no such loophole. Jesus simply said, "the Scripture cannot be broken" (Jn. 10:35). How sharp the contrast between the true word of God and a fraud.