"For whatsoever things were written aforetime were written for our learning, that we through patience and comfort of the scriptures might have hope." (Rom. 15:4.)
"Now all these things happened unto them for ensamples: and they are written for our admonition, upon whom the ends of the world are come." (1 Cor. 10:11.)
These two verses plainly teach us that in the apostles' days there were sacred writings, which they could speak of as written for our comfort and instruction. It is well, then, first of all, to see if we can gather from other parts of scripture with certainty what these sacred writings were. As to this, one thing is very striking. It is the way in which our Lord in the days of His flesh referred to "the scriptures." Not only did He say, "Search the scriptures, for in them ye think ye have eternal life, for they are they which testify of me;" but He was wont to appeal to His hearers, saying, "Have ye never read?" "Did you never read?" "What is written in the law?" "How readest thou?" "Have ye not read that which was spoken unto you by God?" ― all evidently referring to sacred writings. Moreover, He not only said, "Moses wrote of me," but He was pleased to rank the "writings" of Moses with His own "words," when He added, "If ye believe not his writings, how shall ye believe my words?" There were writings, then, which our Lord in His ministry frequently authenticated as divinely-given, which He honoured and obeyed, and their authority was to Him final and conclusive. In point of fact, "It is written," when quoting the very words of scripture, was with Him the sword of the Spirit to resist Satan in all his temptations.
There were writings, then, which our Lord used, honoured, and obeyed, and commended to His hearers as testifying of Himself, scripture which must be fulfilled, and, because divinely-given, infinite, and pure, and holy. Now these were the books of the Old Testament, for the New Testament was not then in existence.
The external evidence of the divine authenticity of scripture is very weighty, especially when we consider that to the Jews were "committed the oracles of God," and from time immemorial to the present, it is well known that they have retained the different books of the Old Testament pretty much as we have them, and regard them as given to them by Jehovah. Our object now, however, is not to look so much at the external evidence, as to the internal testimony the scriptures give of their being the word of God. It is interesting, however to know, that in the early centuries of what is called the Christian Era, there is abundance of proof from the writers of that time, that they quoted largely from the books of the New Testament. It is said also, that Lord Halles, a Scotchman, having searched the writings of the so-called Christian Fathers who lived during three hundred years after Christ, found, with all their blunders, nearly all the writings of the New Testament as we have them in different parts of their books.
The attempt to prove by human reasoning and external evidence that the scripture is God's word, would be just as absurd as lighting a candle to look at the sun. Every one knows, except he be blind, that the sun gives light and heat. We know nothing of the sun without these effects. So every honest mind that has ears to hear, and gets before God, finds scripture so searching, that it commends itself to his conscience as being the word of God. He finds it quick and powerful, and sharper than any two-edged sword.