The glory of God is the beauty of His spirit. It is not an aesthetic beauty or a material beauty, but it is the beauty that emanates from His character, from all that He is. Isaiah 43:7 says that God created us for His glory. In context with the other verses, it can be said that man “glorifies” God because through man, God’s glory can be seen in things such as love, music, heroism and so forth—things belonging to God that we are carrying “in jars of clay” (2 Corinthians 4:7).
In the human/earthly sense, glory is a beauty or vibrancy that rests upon the material of the earth (Psalm 37:20, Psalm 49:17), and in that sense, it fades. But the reason it fades is that material things do not last. They die and wither, but the glory that is in them belongs to God, and returns to Him when death or decay takes the material.
In Isaiah 42:8, we see an example of God’s jealousy over His glory. This jealousy for His own glory is what Paul is talking about in Romans 1:21-25 when he speaks of the ways people worship the creature rather than the Creator. In other words, they looked at the object through which God’s glory was coming, and, instead of giving God the credit for it, they worshipped that animal or tree or man as if the beauty it possessed originated from within itself.
This is the mistake many people continue to make: trusting in earthly things, earthly relationships, their own powers or talents or beauty, or the goodness they see in others. But when these things fade and fail as they will inevitably do (being only temporary carriers of the greater glory), these people despair. What we all need to realize is that God’s glory is constant, and as we journey through life we will see it manifest here and there. But it all goes back to God in the end. And the only way to God is through His Son, Jesus Christ.