Hey Gonzo. The Scriptures teach that the Scriptures are the Word of God and all doctrines must be scriptural or they are but heresies.
2Ti:3
12. Yea, and all that will live godly in Christ Jesus shall suffer persecution.
13. But evil men and seducers shall wax worse and worse, deceiving, and being deceived.
14. But continue thou in the things which thou hast learned and hast been assured of, knowing of whom thou hast learned them;
15. And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus.
16. All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
17. That the man of God may be perfect, throughly furnished unto all good works.
And Peter himself;
2 Peter 1:
15. Moreover I will endeavour that ye may be able after my decease to have these things always in remembrance.
16. For we have not followed cunningly devised fables, when we made known unto you the power and coming of our Lord Jesus Christ, but were eyewitnesses of his majesty.
17. For he received from God the Father honour and glory, when there came such a voice to him from the excellent glory, This is my beloved Son, in whom I am well pleased.
18. And this voice which came from heaven we heard, when we were with him in the holy mount.
19. We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts:
20. Knowing this first, that no prophecy of the scripture is of any private interpretation.
21. For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost.
Okay, for the sake of argument, which books of the Bible are inspired? Where is it written in Scripture that Matthew is an inspired book?