Adding to the Scriptures, by Robert Rosskopf

" 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."
(2 Timothy 3)

The word "scripture" has come to represent the canon of books found in the Holy Bible, but originally it just refered to writing - any kind of writing.  Our modern word "script" comes from the same Greek word translated as "scripture". 

" 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."  
(2 Peter 1)

This verse in 2nd Peter is a couplet; it says the same thing two different ways.  "Private interpretation" means the "holy men" did not speak of themselves.  The prophecy isn't their own opinion or "interpretation".  Prophecies come from the Holy Ghost.  Implicit in this scripture is the idea that not all scripture comes from the Holy Ghost, but "prophecies" of the scripture always come from the Holy Ghost.  This seems to contradict the scripture in 2nd Timothy, where all scripture is given by "inspiration".  The inspired version of the bible agrees with Vulgate in rendering this scripture slightly different:
"And all scripture given by inspiration of God, is profitable for doctrine, for reproof, for correction, for instruction in righteousness; "
That clears up the conflict, as not all writing is inspired, or "breathed" from God.  It is clear from the following verse that God does command men to write his words, that they may be known.

" 11 For I command all men, both in the east and in the west, and in the north, and in the south, and in the islands of the sea, that they shall write the words which I speak unto them; for out of the books which shall be written I will judge the world, every man according to their works, according to that which is written. "  
(2 Nephi 29)

Sometimes men just write because they want to leave a legacy, and pass on those things that they have learned about god.

"15 And upon these I write the things of my soul, and many of the scriptures which are engraven upon the plates of brass. For my soul delighteth in the scriptures, and my heart pondereth them, and writeth them for the learning and the profit of my children."  (2 Nephi 4)

"4 For whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the scriptures might have hope."  (Romans 15)

Many books have been lost.

"29 Now the acts of David the king, first and last, behold, they are written in the book of Samuel the seer, and in the book of Nathan the prophet, and in the book of Gad the seer,"  (1 Chronicles 29)

"29 Now the rest of the acts of Solomon, first and last, are they not written in the book of Nathan the prophet, and in the prophecy of Ahijah the Shilonite, and in the visions of Iddo the seer against Jeroboam the son of Nebat?"  
(2 Chronicles 9)

"15 Now the acts of Rehoboam, first and last, are they not written in the book of Shemaiah the prophet, and of Iddo the seer concerning genealogies?"  
(2 Chronicles 12)

"34 Now the rest of the acts of Jehoshaphat, first and last, behold, they are written in the book of Jehu the son of Hanani, who is mentioned in the book of the kings of Israel."  
(2 Chronicles 20:34)

There is no reason to believe that the books which have been saved are the only inspired writings, or that all of the books in the common cannon are inspired, or "breathed" by God, or that all of the doctrines revealed by God can be found in our current canon of scripture.

Implicit in the following verse is the promise of additional scripture, as Jesus will send prophets and scribes.

"34 Wherefore, behold, I send unto you prophets, and wise men, and scribes: and some of them ye shall kill and crucify; and some of them shall ye scourge in your synagogues, and persecute them from city to city:"  
(Matthew 23)