An excerpt from "Desiring God.org" entitled, "The Deep Riches and Wisdom and Knowledge of God" by John Piper, states: "
God is rich in at least three senses.
1. God Owns All
First, God owns all that exists that is not God. Psalm 24:1 is the most familiar statement of this truth:
The earth is the Lord’s and the fullness thereof,
the world and those who dwell therein.
But Deuteronomy 10:14 is far more sweeping:
Behold, to the Lord your God belong heaven and the heaven of heavens, the earth with all that is in it.”
2. God Makes All
Second, God is rich in the sense that he made all that is and can make anything he pleases and as much as he pleases out of nothing. “In the beginning, God created the heavens and the earth” (Genesis 1:1; Psalm 8:3; 104:24). In other words, his resources are infinite because the resources out of which he can make anything is nothingness, and there is an incalculable “amount” of nothingness.
3. God Is the Infinite Treasure of the Universe
Third, God is rich in the sense that he himself is the infinite Treasure of the universe. God does not have to create anything or to own anything in order to be rich. He is himself of infinite value. And since he exists as a Trinity of persons in one Godhead, he has been able to enjoy the riches of his own glory from all eternity existing in the other persons of the Godhead.
This article may be viewed at: The Deep Riches and Wisdom and Knowledge of God/desiringgod.org
Reference: Romans 11:33