Isaiah 40:8 says "the word of our God stands forever" (NASB). I can understand the purpose of the Word in this sinful life. But, what is the purpose of the Word lasting forever when we are in the Kingdom and New Earth where sin does not reign in our bodies?
The counsel of God's word is not merely provided to us for instruction or to convey information. The word of God is far more necessary and powerful, and in fact, it is the very thing sustaining all things in existence:
Heb. 1:3 And He is the radiance of His glory and the exact representation of His nature, and upholds all things by the word of His power. When He had made purification of sins, He sat down at the right hand of the Majesty on high,
Matt. 4:3 And the tempter came and said to Him, “If You are the Son of God, command that these stones become bread.”
Matt. 4:4 But He answered and said, “It is written, ‘MAN SHALL NOT LIVE ON BREAD ALONE, BUT ON EVERY WORD THAT PROCEEDS OUT OF THE MOUTH OF GOD.’”
Moreover, although resurrected believers from this age enter the Kingdom without sin, there will be others who enter with sin, according to the Bible, and these will need the knowledge of Christ from Scripture just as we did.
For more information on life in the Kingdom, please watch our Revelation study or read the following articles: