Psalm 12:6,7 “The words of the LORD are pure words: as silver tried in a furnace of earth, purified seven times. Thou shalt keep them, O LORD, thou shalt preserve them from this generation for ever.”
When God wrote His Bible through about 40 men, He wrote it with the intent that it continues forever. This was necessary because it is the only word God gave to mankind, and it is the only message that shows how people can be saved and live forever with God.
If the message would ever become corrupted – other than through the deliberate attempts of some to force it to teach their false and wicked views, the hope of salvation and the standard of truth would be lost. When God wrote the above verses, and many others like it, He staked His own power and reputation on His ability to do what He said.
Note the extent of its purity. In Bible times, when silver went through the purifying process seven times, it was considered to be as pure as possible. God used that illustration to reveal how pure His Word is. When recorded, it contained no mistakes of any kind, not in history, geography, science, mathematics, or any other matter – including creation, prophesy, the Rapture, and the future literal Kingdom of Christ, the judgments, etc.
It should also be noted that the future judgment of believers and of the unsaved (two separate judgments) will be based on the Bible. If the Bible is not relevant today, that would be like saying that God will not judge the world. That, of course, is false.
Jesus is the One Who will judge the world and He will judge based on the Word of God. He told us, in John 12:48: “He that rejecteth me, and receiveth not my words, hath one that judgeth him: the word that I have spoken, the same shall judge him in the last day.”
Finally, the Word cannot change because God cannot change. He is eternal and knows all things. Christians must be guided by the Bible because it is the only way we can know what God wants us to be and to do. Without that guidance, we can be sure we are not pleasing Him. Also, His rewards are for faithfulness to His Word.
Christ will deal very harshly with those who think little of His Word. His Word is relevant through all of time. There is also a severe penalty given at the end of the Book for tampering with or altering it. Here is the warning, from Revelation 22:18,19: “For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book: And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book.”