Isaiah 40

Isaiah 40:7-8:
​ The grass withereth, the flower fadeth: because the spirit of the Lord bloweth upon it: surely the people is grass.
8 The grass withereth, the flower fadeth: but the word of our God shall stand for ever.

​The glory of man is illusory. It fades. Isaiah says: “Surely the people are grass. The grass withers and the flowers fall, but the word of our God stands forever.” (Isaiah 40:7-8).
Paul concurs. He says God has intentionally made man “subject to vanity.” (Romans 8:20). We like things that have no value. God says: “How long will you people refuse to respect me? You love foolish things, and you run after what is worthless.” (Psalm 4:2). 
We spend our lives engaged in worthless pursuits. We worship “unrighteous mammon.” (Luke 16:9). We are led astray by “the deceitfulness of riches.” (Matthew 13:22). These riches are “uncertain.” (1 Timothy 6:17). They “make themselves wings; they fly away like an eagle toward heaven.” (Proverbs 23:5).
We put our treasures on earth, “where moth and rust destroy and where thieves break in and steal” (Matthew 6:19). But we ignore God, “the Desire of All Nations.” (Haggai 2:7). “We are not mindful of the things of God, but the things of men.” (Matthew 16:23
​Like the foolish Chaldeans “who rejoice in their ships” (Isaiah 43:14), we rejoice in our cars, our houses, and our possessions. But Jesus says we should rejoice for only one reason: “because (our) names are written in heaven.” (Luke 10:20).
He points out that: “What is highly esteemed among men is an abomination in the sight of God.” (Luke 16:15). Everything man-made is rubbish to God. Nevertheless, we are mesmerised by them. - Premium Times

The word of God is immutable. When Rocky Mountains have crumbled into dust, Gods word will abide. It will stand because it is truth. No truth can pass away. All nature is made up of numerous elements, music on a scale of various tones, and mathematics on two rules: addition and subtraction. The skeptic is converted once he discovers the law to which he can neither add or take away from. An infidel once sought to acquaint himself with the truth of the Bible. "I have been trying to see if I can add or take away anything from it in order to make it better. Sir, I cannot. It is perfect." This, to me, is the best way to define "perfect": I can add nothing to it, or take way from it, in order to make it better. If we understand the that Biblical record is not a history of natural occurrences of science, geography, or even of man, and we see that it's purpose is to reveal the character of God, then and only then will we see its perfection.

Isaiah 40:31:
But they that wait upon the LORD shall renew their strength; they shall mount up with wings as eagles; they shall run, and not be weary; and they.

​"Wait" in the Hebrew means "to bind together, tangle, entwine, or tarry expectantly" (some translations use the word "hope"). "Renew" in the Hebrew original means "to change." An old eagles feathers in the latter years of his life grow old and mottled and eventually begin to fall out.. His beak grows dull and his talons blunt. He cannot fly as high as he used to, nor can he tear the prey with his beak or grip the prey with his talons as before. Instinct tells him to fly high into the mountains and to find a cave where he can be all alone. There in that cave he will begin scraping his feathers, beak, and talons on a rock until he completely scrapes them away. He does not eat or drink, but rather fasts. It is a very painful and homely experience. The eagle simply waits, for he knows through instinct that his feathers, beak and talons will eventually grow back to normality. When the eagle emerges from his time of waiting and stretches his wings for all the world to see, he looks like a brand new young eagle. He then mounts up on wings and flies again to the heights he once knew.