Why do we Christians believe the Bible is the word of God?
Is it necessary for a written document to be clamed by the writer as inspired, to be considered Scripture? Or are there other criteria that can be used?

Because of course the Old testement contains the history of Gods relationship with man up to the point that christ was born.

But many things can be inspired from God, many ministers may have a word of wisdom from God. But the early church reviewed for the new testement the writtings of the early apostles and they found the ones that were the most used and known and proven at the time and included those.

Other writings can be inspired, but are not held to the level of the scripture which is the guide line.
And while others may have options of right and wrong with out it, they can often be in errror and living in a immoral method is they rely on their own judgements.

Becuase of course the Old testement contains the history of Gods relationship with man up to the point that christ was born.

But many things can be inspired from God, many ministers may have a word of wisdom from God. But the early church reviewed for the new testement the writtings of the early apostles and they found the ones that were the most used and known and proven at the time and included those.

We are on the same page.

This is at the heart of many of the divisions between Christians today. I know the Bible is the Word of God because I recognize the authority of the early church to make such a decision.

And of course there are those that hate God so much , they will do anything to weaken his word. And often we find those people in the church and even behind the pulpit. There was a poll in one church in Europe a few years ago and about 10 percent of their preachers admitted they did not believe in God. About 30 percent did not believe there was a hell. And we remember the bible tells us that the good and bad are together and God will seperage them on the last day, Plus of course we are also warned that religious that are pleasing to what man wants to hear will arise. And of course many want the love but do not wish to be the sheep who follow the voice of Jesus in their actions either.

What other collection of books written by so many different authors over such long period are in such complete agreement? Fulfilled prophecy is proof. The fact that when the Bible is actually put into practice, it works. Jesus fulfilled, illumintated and fulfilled the "law and prophets". The Church exists today in spite of all the violent efforts to stamp it out.

I can give you seven reasons the bible is trustworthy. PM me to tell which one.
Logical reason
Scientific reason
Historical reason
Prophetic reason
Christological reason
Providential reason
Personal reason- like I said PM me and ill be more than happy to help
:)